EXHIBIT 10.75
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                         SBA TELECOMMUNICATIONS, INC.

                             AMENDED AND RESTATED
                               CREDIT AGREEMENT


                           Dated as of June 29, 1998


                            BANKBOSTON, N.A., Agent

                      FIRST UNION NATIONAL BANK, Co-Agent

                         FLEET NATIONAL BANK, Co-Agent

                               -----------------

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                          BANCBOSTON SECURITIES INC.,
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                         Syndication Agent and Manager

 
                                TABLE OF CONTENTS
 
 
                                                                                                         Page

                                                                                                    
1.    AMENDMENT AND RESTATEMENT; DEFINITIONS................................................................1
      --------------------------------------
      1.1.  Amendment and Restatement.......................................................................1
            -------------------------
      1.2.  Definitions; Certain Rules of Construction......................................................2
            ------------------------------------------

2.    THE CREDITS..........................................................................................27
      -----------
      2.1.  Revolving Credit...............................................................................27
            ----------------
            2.1.1.   Revolving Loan........................................................................27
                     --------------
            2.1.2.   Maximum Amount of Revolving Credit....................................................27
                     ----------------------------------
            2.1.3.   Borrowing Requests....................................................................29
                     ------------------
            2.1.4.   Revolving Notes.......................................................................30
                     ---------------
      2.2.  Incremental Credit.............................................................................30
            ------------------
            2.2.1.   Request for Incremental Facility......................................................30
                     --------------------------------
            2.2.2.   Incremental Facility..................................................................30
                     --------------------
            2.2.3.   Incremental Borrowing Requests........................................................31
                     ------------------------------
            2.2.4.   Incremental Revolving Notes...........................................................31
                     ---------------------------
            2.2.5.   Incremental Term Loan.................................................................31
                     ---------------------
            2.2.6.   Incremental Term Notes................................................................32
                     ----------------------
      2.3.  Letters of Credit..............................................................................32
            -----------------
            2.3.1.   Issuance of Letters of Credit.........................................................32
                     -----------------------------
            2.3.2.   Requests for Letters of Credit........................................................32
                     ------------------------------
            2.3.3.   Form and Expiration of Letters of Credit..............................................32
                     ----------------------------------------
            2.3.4.   Lenders' Participation in Letters of Credit...........................................33
                     -------------------------------------------
            2.3.5.   Presentation..........................................................................33
                     ------------
            2.3.6.   Payment of Drafts.....................................................................33
                     -----------------
            2.3.7.   Uniform Customs and Practice..........................................................34
                     ----------------------------
            2.3.8.   Subrogation...........................................................................35
                     -----------
            2.3.9.   Modification, Consent, etc............................................................35
                     --------------------------
      2.4.  Application of Proceeds........................................................................36
            -----------------------
            2.4.1.   Revolving Loan........................................................................36
                     --------------
            2.4.2.   Incremental Facility..................................................................36
                     --------------------
            2.4.3.   Letters of Credit.....................................................................36
                     -----------------
            2.4.4.   Specifically Prohibited Applications..................................................36
                     ------------------------------------
      2.5.  Nature of Obligations of Lenders to Make Extensions of Credit..................................36
            -------------------------------------------------------------

3.    INTEREST; EURODOLLAR PRICING OPTIONS; FEES...........................................................37
      ------------------------------------------
      3.1.  Interest.......................................................................................37
            --------
      3.2.  Eurodollar Pricing Options.....................................................................37
            --------------------------
            3.2.1.   Election of Eurodollar Pricing Options................................................37
                     --------------------------------------
            3.2.2.   Notice to Lenders and Company.........................................................38
                     -----------------------------

 


                                      -i-

 
 
 

                                                                                                         Page

                                                                                                
            3.2.3.   Selection of Eurodollar Interest Periods..............................................38
                     ----------------------------------------
            3.2.4.   Additional Interest...................................................................39
                     -------------------
            3.2.5.   Violation of Legal Requirements.......................................................39
                     -------------------------------
            3.2.6.   Funding Procedure.....................................................................40
                     -----------------
      3.3.  Commitment Fees................................................................................40
            ---------------
            3.3.1.   Revolving Loan........................................................................40
                     --------------
            3.3.2.   Incremental Revolving Loan............................................................40
                     --------------------------
      3.4.  Letter of Credit Fees..........................................................................40
            ---------------------
      3.5.  Changes in Circumstances; Yield Protection.....................................................41
            ------------------------------------------
            3.5.1.   Reserve Requirements, etc.............................................................41
                     -------------------------
            3.5.2.   Taxes.................................................................................41
                     -----
            3.5.3.   Capital Adequacy......................................................................42
                     ----------------
            3.5.4.   Regulatory Changes....................................................................42
                     ------------------
            3.5.5.   Compensation Claims...................................................................42
                     -------------------
            3.5.6.   Mitigation............................................................................43
                     ----------
      3.6.  Computations of Interest and Fees..............................................................43
            ---------------------------------

4.    PAYMENT..............................................................................................43
      -------
      4.1.  Payment at Maturity............................................................................43
            -------------------
      4.2.  Scheduled Required Prepayments.................................................................43
            ------------------------------
      4.3.  Contingent Required Prepayments................................................................43
            -------------------------------
            4.3.1.   Excess Credit Exposure................................................................43
                     ----------------------
            4.3.2.   Net Asset Sale Proceeds...............................................................44
                     -----------------------
            4.3.3.   Net Debt Proceeds.....................................................................44
                     -----------------
            4.3.4.   Net Equity Proceeds...................................................................44
                     -------------------
            4.3.5.   Excess Cash Flow......................................................................44
                     ----------------

      4.4.  Voluntary Prepayments..........................................................................44
            ---------------------
      4.5.  Letters of Credit..............................................................................45
            -----------------
      4.6.  Reborrowing; Application of Payments, etc......................................................45
            -----------------------------------------
            4.6.1.   Reborrowing...........................................................................45
                     -----------
            4.6.2.   Order of Application..................................................................45
                     --------------------
            4.6.3.   Payment with Accrued Interest, etc....................................................46
                     ----------------------------------
            4.6.4.   Payments for Lenders..................................................................46
                     --------------------

5.    CONDITIONS TO EXTENDING CREDIT.......................................................................46
      ------------------------------
      5.1.  Conditions on Effective Date...................................................................46
            ----------------------------
            5.1.1.   Notes.................................................................................46
                     -----
            5.1.2.   Payment of Fees.......................................................................46
                     ---------------
            5.1.3.   Legal Opinions........................................................................46
                     --------------
            5.1.4.   Guarantee and Security Agreement; Parent Pledge and Subordination
                     -----------------------------------------------------------------
      Agreement, etc.......................................................................................47
      --------------
            5.1.5.   Perfection of Security................................................................47
                     ----------------------
            5.1.6.   Solvency..............................................................................47
                     --------

 
                                     -ii-

 
 

                                                                                                   
            5.1.7.   No Material Adverse Change in Syndication Market......................................48
                     ------------------------------------------------
            5.1.8.   Proper Proceedings....................................................................48
                     ------------------
            5.1.9.   General...............................................................................48
                     -------
      5.2.  Conditions to Each Extension of Credit.........................................................48
            --------------------------------------
            5.2.1.   Officer's Certificate.................................................................48
                     ---------------------
            5.2.2.   Legality, etc.........................................................................48
                     -------------

6.    GENERAL COVENANTS....................................................................................49
      -----------------
      6.1.  Taxes and Other Charges; Accounts Payable......................................................49
            -----------------------------------------
            6.1.1.   Taxes and Other Charges...............................................................49
                     -----------------------
            6.1.2.   Accounts Payable......................................................................49
                     ----------------
      6.2.  Conduct of Business, etc.......................................................................49
            ------------------------
            6.2.1.   Types of Business.....................................................................49
                     -----------------
            6.2.2.   Maintenance of Properties.............................................................50
                     -------------------------
            6.2.3.   Statutory Compliance..................................................................50
                     --------------------
            6.2.4.   Compliance with Material Agreements...................................................50
                     -----------------------------------
      6.3.  Insurance......................................................................................50
            ---------
            6.3.1.   Property Insurance....................................................................50
                     ------------------
            6.3.2.   Liability Insurance...................................................................51
                     -------------------
            6.3.3.   Key Executive Life Insurance..........................................................51
                     ----------------------------
            6.3.4.   Flood Insurance.......................................................................51
                     ---------------
      6.4.  Financial Statements and Reports...............................................................51
            --------------------------------
            6.4.1.   Annual Reports........................................................................51
                     --------------
            6.4.2.   Quarterly Reports.....................................................................53
                     -----------------
            6.4.3.   Monthly Reports.......................................................................54
                     ---------------
            6.4.4.   Tower Acquisition Reports.............................................................54
                     -------------------------
            6.4.5.   Other Reports.........................................................................54
                     -------------
            6.4.6.   Notice of Litigation, Defaults, etc...................................................55
                     -----------------------------------
            6.4.7.   ERISA Reports.........................................................................55
                     -------------
            6.4.8.   Other Information.....................................................................56
                     -----------------
      6.5.  Certain Financial Tests........................................................................56
            -----------------------
            6.5.1.   Consolidated Total Debt to Consolidated Adjusted EBITDA...............................56
                     -------------------------------------------------------
            6.5.2.   Consolidated Adjusted EBITDA to Consolidated Pro Forma Interest
                     ---------------------------------------------------------------
      Expense..............................................................................................57
      -------
            6.5.3.   Consolidated EBITDA to Consolidated Fixed Charges.....................................57
                     -------------------------------------------------
            6.5.4.   Consolidated Adjusted EBITDA..........................................................57
                     ----------------------------
            6.5.5.   Consolidated Adjusted EBITDA to Consolidated Pro Forma Fixed
                     ------------------------------------------------------------
      Charges..............................................................................................58
      -------
            6.5.6.   Overdue Tower Construction Receivables................................................58
                     --------------------------------------
            6.5.7.   Capital Expenditures..................................................................58
                     --------------------
            6.5.8.   Executive Management Compensation.....................................................58
                     ---------------------------------
      6.6.  Indebtedness...................................................................................58
            ------------
      6.7.  Guarantees; Letters of Credit..................................................................60
            -----------------------------


 



                                     -iii-

 
 

                                                                                                   
      6.8.  Liens..........................................................................................60
            -----
      6.9.  Investments and Acquisitions...................................................................62
            ----------------------------
      6.10. Distributions..................................................................................63
            -------------
      6.11. Asset Dispositions and Mergers.................................................................64
            ------------------------------
      6.12. Issuance of Stock by Subsidiaries or the Company; Subsidiary Distributions.....................65
            --------------------------------------------------------------------------
            6.12.1.   Issuance of Stock by Subsidiaries or the Company.....................................65
                      ------------------------------------------------
            6.12.2.   No Restrictions on Subsidiary Distributions..........................................65
                      -------------------------------------------
      6.13. Voluntary Prepayments of Other Indebtedness....................................................65
            -------------------------------------------
      6.14. Derivative Contracts...........................................................................65
            --------------------
      6.15. Negative Pledge Clauses........................................................................66
            -----------------------
      6.16. ERISA, etc.....................................................................................66
            ----------
      6.17. Transactions with Affiliates...................................................................66
            ----------------------------
      6.18. Interest Rate Protection.......................................................................66
            ------------------------
      6.19. Environmental Laws.............................................................................67
            ------------------
            6.19.1.   Compliance with Law and Permits......................................................67
                      -------------------------------
            6.19.2.   Notice of Claims, etc................................................................67
                      ---------------------
      6.20. Tower Matters..................................................................................67
            -------------
            6.20.1.   Tower Construction Requirements......................................................67
                      -------------------------------
            6.20.2.   No Removal of Towers.................................................................67
                      --------------------
            6.20.3.   Pledged Towers.  ....................................................................67
                      --------------
      6.21. Series A Preferred Stock Redemptions...........................................................68
            ------------------------------------
      6.22. Restricted Operations of Parent................................................................68
            -------------------------------

7.    REPRESENTATIONS AND WARRANTIES.......................................................................69
      ------------------------------
      7.1.  Organization and Business......................................................................69
            -------------------------
            7.1.1.   The Company...........................................................................69
                     -----------
            7.1.2.   Subsidiaries..........................................................................69
                     ------------
            7.1.3.   The Parent............................................................................69
                     ----------
            7.1.4.   Qualification.........................................................................70
                     -------------
            7.1.5.   Capitalization........................................................................70
                     --------------
      7.2.  Financial Statements and Other Information; Material Agreements................................70
            ---------------------------------------------------------------
            7.2.1.   Financial Statements and Other Information............................................70
                     ------------------------------------------
            7.2.2.   Material Agreements...................................................................71
                     -------------------
      7.3.  Agreements Relating to Financing Debt, Investments, etc........................................71
            -------------------------------------------------------
      7.4.  Changes in Condition...........................................................................72
            --------------------
      7.5.  Title to Assets................................................................................72
            ---------------
      7.6.  Operations in Conformity With Law, etc.........................................................72
            --------------------------------------
      7.7.  Litigation.....................................................................................73
            ----------
      7.8.  Authorization and Enforceability...............................................................73
            --------------------------------
      7.9.  No Legal Obstacle to Agreements................................................................73
            -------------------------------
      7.10. Defaults.......................................................................................74
            --------
      7.11. Licenses, etc..................................................................................74
            -------------
      7.12. Tax Returns....................................................................................75
            -----------
 

                                     -iv-

 
 

                                                                                                   
      7.13. Certain Business Representations...............................................................75
            --------------------------------
            7.13.1.   Labor Relations......................................................................75
                      ---------------
            7.13.2.   Antitrust............................................................................75
                      ---------
            7.13.3.   Tower Sites..........................................................................75
                      -----------
            7.13.4.   Real Property Leases.................................................................75
                      --------------------
            7.13.5.   FCC and FAA Matters..................................................................76
                      -------------------
      7.14. Environmental Regulations......................................................................76
            -------------------------
            7.14.1.   Environmental Compliance.............................................................76
                      ------------------------
            7.14.2.   Environmental Litigation.............................................................76
                      ------------------------
            7.14.3.   Hazardous Material...................................................................77
                      ------------------
            7.14.4.   Environmental Condition of Properties................................................77
                      -------------------------------------
      7.15. Pension Plans..................................................................................77
            -------------
      7.16. Government Regulation; Margin Stock............................................................78
            -----------------------------------
            7.16.1.   Government Regulation................................................................78
                      ---------------------
            7.16.2.   Margin Stock.........................................................................78
                      ------------
      7.17. Disclosure.....................................................................................78
            ----------

8.    DEFAULTS.............................................................................................78
      --------
      8.1.  Events of Default..............................................................................78
            -----------------
            8.1.1.   Payment...............................................................................78
                     -------
            8.1.2.   Specified Covenants...................................................................78
                     -------------------
            8.1.3.   Other Covenants.......................................................................79
                     ---------------
            8.1.4.   Representations and Warranties........................................................79
                     ------------------------------
            8.1.5.   Cross Default, etc....................................................................79
                     ------------------
            8.1.6.   Ownership; Liquidation; etc...........................................................80
                     ---------------------------
            8.1.7.   Enforceability, etc...................................................................80
                     -------------------
            8.1.8.   Judgments.............................................................................80
                     ---------
            8.1.9.   ERISA.................................................................................80
                     -----
            8.1.10.  Bankruptcy, etc.......................................................................81
                     ---------------
      8.2.  Certain Actions Following an Event of Default..................................................81
            ---------------------------------------------
            8.2.1.   Terminate Obligation to Extend Credit.................................................82
                     -------------------------------------
            8.2.2.   Specific Performance; Exercise of Rights..............................................82
                     ----------------------------------------
            8.2.3.   Acceleration..........................................................................82
                     ------------
            8.2.4.   Enforcement of Payment; Credit Security; Setoff.......................................82
                     -----------------------------------------------
            8.2.5.   Cumulative Remedies...................................................................83
                     -------------------
      8.3.  Annulment of Defaults..........................................................................83
            ---------------------
      8.4.  Waivers........................................................................................83
            -------

9.    EXPENSES; INDEMNITY..................................................................................83
      -------------------
      9.1.  Expenses.......................................................................................83
            --------
      9.2.  General Indemnity..............................................................................84
            -----------------
      9.3.  Indemnity With Respect to Letters of Credit....................................................85
            -------------------------------------------

 

                                      -v-

 
 

                                                                                                   
10.   OPERATIONS; AGENT....................................................................................85
      -----------------
      10.1. Interests in Credits...........................................................................85
            --------------------
      10.2. Agent's Authority to Act, etc..................................................................85
            -----------------------------
      10.3. Company to Pay Agent, etc......................................................................85
            -------------------------
      10.4. Lender Operations for Advances, Letters of Credit, etc.........................................85
            ------------------------------------------------------
            10.4.1.   Advances.............................................................................86
                      --------
            10.4.2.   Letters of Credit....................................................................86
                      -----------------
            10.4.3.   Agent to Allocate Payments, etc......................................................86
                      --------------------------------
            10.4.4.   Delinquent Lenders; Nonperforming Lenders............................................87
                      -----------------------------------------
      10.5. Sharing of Payments, etc.......................................................................87
            ------------------------
      10.6. Agent's Resignation............................................................................88
            ------------------- 
      10.7. Concerning the Agent...........................................................................88
            --------------------
            10.7.1.   Action in Good Faith, etc............................................................88
                      -------------------------
            10.7.2.   No Implied Duties, etc...............................................................89
                      ----------------------
            10.7.3.   Validity, etc........................................................................89
                      -------------
            10.7.4.   Compliance...........................................................................89
                      ----------
            10.7.5.   Employment of Agents and Counsel.....................................................89
                      --------------------------------
            10.7.6.   Reliance on Documents and Counsel....................................................90
                      ---------------------------------
            10.7.7.   Agent's Reimbursement................................................................90
                      ---------------------
      10.8. Rights as a Lender.............................................................................90
            ------------------
      10.9. Independent Credit Decision....................................................................90
            ---------------------------
      10.10.Indemnification................................................................................91
            ---------------

11.   SUCCESSORS AND ASSIGNS; LENDER ASSIGNMENTS AND PARTICIPATIONS........................................91
      -------------------------------------------------------------
      11.1. Assignments by Lenders.........................................................................91
            ----------------------
            11.1.1.   Assignees and Assignment Procedures..................................................91
                      -----------------------------------
            11.1.2.   Terms of Assignment and Acceptance...................................................92
                      ----------------------------------
            11.1.3.   Register.............................................................................93
                      --------
            11.1.4.   Acceptance of Assignment and Assumption..............................................94
                      ---------------------------------------
            11.1.5.   Federal Reserve Bank.................................................................94
                      --------------------
            11.1.6.   Further Assurances...................................................................94
                      ------------------
      11.2. Credit Participants............................................................................94
            -------------------
      11.3. Replacement of Lender..........................................................................95
            --------------------- 

12.   CONFIDENTIALITY......................................................................................96
      ---------------

13.   FOREIGN LENDERS......................................................................................97
      ---------------

14.   NOTICES..............................................................................................97
      -------

15.   AMENDMENTS, CONSENTS, WAIVERS, ETC...................................................................98
      ----------------------------------
      15.1. Lender Consents for Amendments.................................................................98
            ------------------------------
      15.2. Course of Dealing; No Implied Waivers.........................................................100
            -------------------------------------

 

                                     -vi-

 
 

                                                                                                     
16.   NO STRICT CONSTRUCTION..............................................................................100
      ----------------------

17.   DEFEASANCE..........................................................................................100
      ----------

18.   VENUE; SERVICE OF PROCESS...........................................................................100
      -------------------------

19.   WAIVER OF JURY TRIAL................................................................................101
      --------------------

20.   GENERAL.............................................................................................102
      -------

 

                                     -vii-

 
                                   EXHIBITS

1.1            -  Borrower Assumption Agreement

2.1.4          -  Revolving Note

2.2.4          -  Incremental Revolving Note

2.2.6          -  Incremental Term Note

5.1.4A         -  Guarantee and Security Agreement

5.1.4B         -  Parent Pledge and Subordination Agreement

5.2.1          -  Officer's Certificate

6.4.           -  Compliance Certificate

6.6.8          -  Seller Subordination Terms

6.20.3A        -  Mortgage

6.20.3B        -  Leasehold Mortgage

6.20.3C        -  Estoppel and Consent Letter

6.20.3D        -  Local Real Estate Opinion

7.1            -  Company, its Parent and its Subsidiaries

7.2.2          -  Material Agreements

7.3            -  Financing Debt, Certain Investments, etc.

7.13.3         -  Tower Sites

7.14           -  Hazardous Material Sites

7.15           -  Multi-employer and Defined Benefit Plans

10.1           -  Percentage Interests

11.1.1         -  Assignment and Acceptance

                                    -viii-

 
                          SBA TELECOMMUNICATIONS, INC.

                     AMENDED AND RESTATED CREDIT AGREEMENT


     This Agreement, dated as of June 29, 1998 is among SBA Telecommunications,
Inc., a Florida corporation, the Subsidiaries of SBA Telecommunications, Inc.
from time to time party hereto, SBA Communications Corporation, a Florida
corporation and the parent company of SBA Telecommunications, Inc., the Lenders
from time to time party hereto and BankBoston, N.A., both in its capacity as a
Lender and in its capacity as agent for itself and the other Lenders. The
parties agree as follows:

     Recitals:  Pursuant to this Agreement, the Lenders are extending to the
     --------                                                               
Company a $55,000,000 revolving credit facility, including a $50,000,000
suballotment for letters of credit. In addition, the respective Lenders, each in
its own discretion, may elect to extend to the Company an incremental revolving
credit facility in an aggregate maximum amount of $55,000,000, which incremental
revolving credit facility would convert to a term loan on the second anniversary
of the first advance thereunder.  All the credit facilities mature on June 29,
2005.  These credit facilities are guaranteed by the Company's Domestic
Subsidiaries and are secured by liens on substantially all the assets of the
Company and its Domestic Subsidiaries (including the stock of the Company and
the Company's Subsidiaries and, from and after the Revolving Loan Availability
Date, real estate on which Towers contributing at least 80% of Consolidated Site
Leasing Revenues are located) and a pledge by the Parent of the stock of the
Company.  The proceeds of the credit facilities may be used to acquire and
construct Towers, to acquire Tower Companies, for working capital and for
general corporate purposes, as provided herein.

 1.  AMENDMENT AND RESTATEMENT; DEFINITIONS.
     -------------------------------------- 

     1.1.  Amendment and Restatement.  Effective as of the Effective Date, this
           -------------------------                                           
Agreement amends and restates in its entirety the Credit Agreement dated as of
August 8, 1997, as amended and in effect on the date hereof prior to giving
effect to this Agreement (the "Original Credit Agreement"), among the Parent,
its Subsidiaries and a group of lenders for which BankBoston, N.A. is acting as
agent.  On the Effective Date the Company and the Parent will enter into an
assignment, assumption and release agreement with the Agent in substantially the
form of Exhibit 1.1 (the "Borrower Assumption Agreement"), and the Lenders will
                          -----------------------------                        
make such assignments and other arrangements among themselves, so that the Notes
and Letter of Credit Exposure will be owed only by the Company (and the Parent
shall be released therefrom) and will be held by the Lenders in accordance with
their Percentage Interests.  Amounts in respect of interest, commitment fees,
Letter of Credit fees and other amounts payable hereunder shall be payable in
accordance with the terms of the Original

 
Credit Agreement as in effect prior to the amendment and restatement on the
Effective Date for periods prior to the Effective Date and in accordance with
this Agreement (as it amends and restates the Original Credit Agreement) for
periods from and after the Effective Date.

     1.2.  Definitions; Certain Rules of Construction. Certain capitalized terms
           ------------------------------------------                           
are used in this Agreement and in the other Credit Documents with the specific
meanings defined below in this Section 1.  Except as otherwise explicitly
specified to the contrary or unless the context clearly requires otherwise, (a)
the capitalized term "Section" refers to sections of this Agreement, (b) the
capitalized term "Exhibit" refers to exhibits to this Agreement, (c) references
to a particular Section include all subsections thereof, (d) the word
"including" shall be construed as "including without limitation", (e) accounting
terms not otherwise defined herein have the meaning provided under GAAP, (f)
references to a particular statute or regulation include all rules and
regulations thereunder and any successor statute, regulation or rules, in each
case as from time to time in effect, (g) references to a particular Person
include such Person's successors and assigns to the extent not prohibited by
this Agreement and the other Credit Documents and (h) references to "Dollars" or
"$" mean United States Funds.  References to "the date hereof" mean the date
first set forth above.

           1.2.1. "Accumulated Benefit Obligations" means the actuarial present
                   -------------------------------                             
     value of the accumulated benefit obligations under any Plan, calculated in
     accordance with Statement No. 87 of the Financial Accounting Standards
     Board.

           1.2.2. "Affected Lender" is defined in Section 11.3.
                   ---------------                             

           1.2.3. "Affiliate" means, with respect to the Company (or any other
                   ---------                                                  
     specified Person), any other Person directly or indirectly controlling,
     controlled by or under direct or indirect common control with the Company
     (or such specified Person), and shall include (a) any officer or director
     or general partner of the Company (or such specified Person), (b) any
     Person of which the Company (or such specified Person) or any Affiliate (as
     defined in clause (a) above) of the Company (or such specified Person)
     shall, directly or indirectly, beneficially own either (i) at least 10% of
     the outstanding equity securities having the general power to vote or (ii)
     at least 10% of all equity interests or (c) any Person directly or
     indirectly controlling the Company through a management agreement, voting
     agreement or other contract.

           1.2.4. "Agent" means BankBoston in its capacity as agent for the
                   -----                                                   
     Lenders hereunder, as well as its successors and assigns in such capacity
     pursuant to Section 10.6.

           1.2.5. "Agreement" means this Amended and Restated Credit Agreement 
                   --------- 
     as from time to time further amended, modified and in effect.

 
          1.2.6. "Applicable Margin" means, on each day during any month, the
                  -----------------                                          
     percentage in the table below set opposite the ratio which (a) Consolidated
     Total Debt as of the end of the most recent period of four consecutive
     fiscal quarters for which financial statements have been furnished to the
     Lenders in accordance with Sections 6.4.1 and 6.4.2 prior to the first day
     of such month to (b) Consolidated Adjusted EBITDA for such period:


 
 Ratio of Consolidated Total Debt              Base Rate        Eurodollar Rate
  to Consolidated Adjusted EBITDA          Applicable Margin   Applicable Margin
- -----------------------------------        ------------------  ------------------
                                                         
 
   Greater than 550%                             2.250%              3.250%
 
   Less than or equal to 550% but                2.250%              3.000%
     greater than 500%
 
   Less than or equal to 500% but                1.750%              2.500%
     greater than 400%
 
   Less than or equal to 400% but                1.250%              2.000%
     greater than 300%
 
   Less than or equal to 300% but                0.750%              1.500%
     greater than 200%
 
   Less than or equal to 200%                    0.000%              1.000%
 

 
Changes in the Applicable Margin shall occur on the first day of each month
after quarterly financial statements have been furnished to the Lenders in
accordance with Sections 6.4.1 or 6.4.2 from time to time.  In the event that
the financial statements required to be delivered pursuant to Section 6.4.1 or
6.4.2, as applicable, are not delivered by the first day of the month after the
due date, then during the period from such first day of such month until the
date upon which they are actually delivered, the Applicable Margin shall be the
maximum amount set forth in the table above.

          1.2.7. "Applicable Rate" means, at any date, the sum of:
                  ---------------                                 

          (a) (i)  with respect to each portion of the Loan subject to a
          Eurodollar Pricing Option, the sum of the Applicable Margin  (which
          may change during the Eurodollar Interest Period for such Eurodollar
          Pricing Option in accordance with the definition of "Applicable
          Margin") plus the Eurodollar Rate with respect to such Eurodollar
                   ----                                                    
          Pricing Option;

                                      -3-

 
               (ii)  with respect to each other portion of the Loan, the sum of
          the Applicable Margin plus the Base Rate;
                                ----               

     plus (b)   an additional 2% per annum effective on the day the Agent
     ----                                                                  
          notifies the Company that the interest rates hereunder are increasing
          as a result of the occurrence and continuance of an Event of Default
          until the earlier of such time as (i) such Event of Default is no
          longer continuing or (ii) such Event of Default is deemed no longer to
          exist, in each case pursuant to Section 8.3.

          1.2.8.  "Assignee" is defined in Section 11.1.1.
                   --------                               

          1.2.9.  "Assignment and Acceptance" is defined in Section 11.1.1.
                   -------------------------                               

          1.2.10. "BankBoston" means BankBoston, N.A.
                   ----------                        

          1.2.11. "Banking Day" means any day other than Saturday, Sunday or a 
                   -----------   
     day on which banks in Boston, Massachusetts are authorized or required by
     law or other governmental action to close and, if such term is used with
     reference to a Eurodollar Pricing Option, any day on which dealings are
     effected in the Eurodollars in question by first-class banks in the inter-
     bank Eurodollar markets in New York, New York.

          1.2.12. "Bankruptcy Code" means Title 11 of the United States Code.
                  ---------------                                           

          1.2.13. "Bankruptcy Default" means an Event of Default referred to in
                   ------------------                                          
     Section 8.1.10.

          1.2.14. "Base Rate" means, on any date, the greater of (a) the rate of
                 ---------                                                    
     interest announced by BankBoston at the Boston Office as its Base Rate or
     (b) the sum of 1/2% plus the Federal Funds Rate.
                         ----                        

          1.2.15. "Borrower Assumption Agreement" is defined in Section 1.1.
                   -----------------------------                            

          1.2.16. "Boston Office" means the principal banking office of 
                   -------------   
     BankBoston in Boston, Massachusetts.

          1.2.17. "By-laws" means all written by-laws, rules, regulations and 
                   -------    
     all other documents relating to the management, governance or internal
     regulation of any Person other than an individual, or interpretive of the
     Charter of such Person, all as from time to time in effect.

                                      -4-

 
          1.2.18. "Capital Expenditures" means, for any period, amounts added or
                   --------------------                                         
     required to be added to the property, plant and equipment or other fixed
     assets account on the Consolidated balance sheet of the Company and its
     Subsidiaries, prepared in accordance with GAAP, in respect of (a) the
     acquisition, construction, improvement or replacement of land, buildings,
     machinery, equipment, leaseholds and any other real or personal property,
     (b) to the extent not included in clause (a) above, materials, contract
     labor and direct labor relating thereto (excluding amounts properly
     expensed as repairs and maintenance in accordance with GAAP) and (c)
     software development costs to the extent not expensed.

          1.2.19. "Capitalized Lease" means any lease which is required to be
                   -----------------                                         
     capitalized on the balance sheet of the lessee in accordance with GAAP,
     including Statement Nos. 13 and 98 of the Financial Accounting Standards
     Board.

          1.2.20. "Capitalized Lease Obligations" means the amount of the
                   -----------------------------                         
     liability reflecting the aggregate discounted amount of future payments
     under all Capitalized Leases calculated in accordance with GAAP, including
     Statement Nos. 13 and 98 of the Financial Accounting Standards Board.

          1.2.21. "Cash Equivalents" means:
                   ----------------        

          (1)   negotiable certificates of deposit, time deposits (including
     sweep accounts), demand deposits and bankers' acceptances having a maturity
     of nine months or less and issued by any United States financial
     institution having capital and surplus and undivided profits aggregating at
     least $100,000,000 and rated at least Prime-1 by Moody's or A-1 by S&P or
     issued by any Lender;

          (2)   corporate obligations having a maturity of nine months or less
     and rated at least Prime-1 by Moody's or A-1 by S&P or issued by any
     Lender;

          (3)   any direct obligation of the United States of America or any
     agency or instrumentality thereof, or of any state or municipality thereof,
     (i) which has a remaining maturity at the time of purchase of not more than
     one year or which is subject to a repurchase agreement with any Lender (or
     any other financial institution referred to in clause (a) above)
     exercisable within one year from the time of purchase and (ii) which, in
     the case of obligations of any state or municipality, is rated at least Aaa
     by Moody's or AAA by S&P;

          (4)   any mutual fund or other pooled investment vehicle rated at
     least Aa by Moody's or AA by S&P which invests principally in obligations
     described above; and

                                      -5-

 
          (5)   any Investment by a Foreign Subsidiary in its local jurisdiction
     comparable to the items described above.

          1.2.22. "CERCLA" means the federal Comprehensive Environmental 
                   ------ 
     Response, Compensation and Liability Act of 1980.

          1.2.23. "Charter" means the articles of organization, certificate of
                   -------                                                    
     incorporation, statute, constitution, joint venture agreement, partnership
     agreement, trust indenture, limited liability company agreement or other
     charter document of any Person other than an individual, each as from time
     to time in effect.

          1.2.24. "Closing Date" means the Incremental Closing Date, the
                   ------------                                         
     Incremental Conversion Date and each other date on which any extension of
     credit is made pursuant to Sections 2.1, 2.2 or 2.3.

          1.2.25. "Code" means the federal Internal Revenue Code of 1986.
                   ----                                                  

          1.2.26. "Commitment" means, with respect to any Lender, such Lender's
                   ----------                                                  
     obligations to extend the respective credits contemplated by Section 2.
     The original Commitments are set forth in Exhibit 10.1 and the subsequent
     Commitments are recorded from time to time in the Register.

          1.2.27. "Commitment Fee Rate" means, with respect to any Payment Date,
                  -------------------                                          
     (a) 0.500% in the event that Consolidated Total Debt on the last day of the
     fiscal quarter ending approximately three months prior to such Payment
     Date, exceeds 300% of Consolidated Adjusted EBITDA for the period of four
     consecutive fiscal quarters ending on the last day of the fiscal quarter
     ending approximately three months prior to such Payment Date and (b) 0.375%
     in all other events.

          1.2.28. "Communications Act" means the federal Communications Act of
                   ------------------                                         
     1934.

          1.2.29. "Company" means SBA Telecommunications, Inc., a Florida
                   -------                                               
     corporation and a Wholly Owned Subsidiary of the Parent.

          1.2.30. "Computation Covenants" means Sections 6.5, 6.6.7, 6.6.8,
                   ---------------------                                   
     6.6.11, 6.6.14, 6.6.15, 6.9.5, 6.10.4, 6.11.6, 6.11.7, 6.16 and 6.20.3.

          1.2.31. "Consolidated" and "Consolidating", when used with reference
                   ------------       -------------    
     to any term, mean that term as applied to the accounts of the Company (or
     other specified Person) and all of its Subsidiaries (or other specified
     group of Persons), or such of its Subsidiaries as may be specified,
     consolidated (or combined) or consolidating (or 

                                      -6-

 
     combining), as the case may be, in accordance with GAAP and with
     appropriate deductions for minority interests in Subsidiaries.

          1.2.32. "Consolidated Adjusted EBITDA" means, for any period, the 
                   ----------------------------     
     total of Consolidated EBITDA minus Consolidated Site Leasing Cash Flow plus
                                  -----                                     ----
     Consolidated Annualized Site Leasing Cash Flow.

          1.2.33. "Consolidated Annualized Site Leasing Cash Flow" means, for 
                   ----------------------------------------------      
     any fiscal quarter, the product of (a) Consolidated Site Leasing Cash Flow
     for such fiscal quarter multiplied by (b) four.

          1.2.34. "Consolidated EBITDA" means, for any period, the sum of:
                   -------------------                                    

               (1)   Consolidated Net Income;
plus
- ----

               (2)   all amounts deducted in computing such Consolidated Net
          Income in respect of:

               (1)   depreciation, amortization and other non-cash charges,

               (2)   Consolidated Interest Expense (including Distributions
          described in Section 6.10.4 in respect of interest expense of the
          Parent), and

               (3)   taxes based upon or measured by net income (including
          Distributions described in Section 6.10.5 in respect of such taxes of
          the Parent).

          1.2.35. "Consolidated Excess Cash Flow" means, for any period, the 
                   -----------------------------     
     total of:
 
           (a)  Consolidated EBITDA,
           
     minus (b)  Capital Expenditures,
     -----
 
     minus (c)  Consolidated Fixed Charges (but in no event including contingent
     -----
                prepayments required by Section 4.3),
 
     minus (d)  voluntary prepayments of the Incremental Term Notes and other
     -----
                term Financing Debt of the Company and its Subsidiaries
                permitted by this Agreement,
 
 
     minus (e)  $2,500,000.                                            
     -----

                                      -7-

 
          1.2.36. "Consolidated Fixed Charges" means, for any period, the sum 
                   --------------------------     
          of:
        
                (1) Consolidated Interest Expense,
 
plus      (b)   Non-Tower Capital Expenditures,
- ----
 
plus      (c)  the aggregate amount of all mandatory scheduled payments, 
- ----
               mandatory scheduled prepayments, sinking fund payments and
               mandatory reductions in revolving loans as a result of reductions
               in revolving credit availability, all with respect to
               Consolidated Total Debt, including payments in the nature of
               principal under Capitalized Leases, but in no event including
               contingent prepayments required by Section 4.3,
 
 plus     (d)  taxes based upon or measured by net income that are actually
 ----                                                                     
               paid in cash,

plus      (e)  Distributions paid in cash to the Parent, any of its
- ----                                                               
               stockholders or any of its Subsidiaries (other than the Company
               or any of its Subsidiaries), including Distributions described in
               Sections 6.10.4 or 6.10.5 in respect of interest expense and
               taxes, respectively, of the Parent, but without duplication of
               the items described in clauses (a) and (d) above.

          1.2.37. "Consolidated Interest Expense" means, for any period, the 
                   -----------------------------   
total of:

               (1) the aggregate amount of interest, including commitment fees,
               payments in the nature of interest under Capitalized Leases and
               net payments under Interest Rate Protection Agreements, accrued
               by the Company and its Subsidiaries (whether such interest is
               reflected as an item of expense or capitalized, but excluding PIK
               Interest) in accordance with GAAP on a Consolidated basis
               (including Distributions described in Section 6.10.4 in respect
               of interest expense of the Parent),

minus     (b)  to the extent otherwise included in clause (a) above, the
- -----                                                                   
               amortization of deferred financing fees, original issue discount
               relating to Indebtedness and accrued interest on Indebtedness not
               paid in cash to the extent permitted by the terms, including
               subordination terms, of such Indebtedness (including PIK
               Interest)

plus (c)       actual cash payments with respect to accrued and unpaid
- ----                                                                  
               interest (including PIK Interest) that has previously reduced
               Consolidated Interest Expense pursuant to clause (b) above.

                                      -8-

 
          1.2.38. "Consolidated Net Income" means, for any period, the net 
                   -----------------------  
     income (or loss) of the Company and its Subsidiaries, determined in
     accordance with GAAP on a Consolidated basis, including (a) the income (or
     loss) of any Person accrued prior to the date such Person becomes a
     Subsidiary or is merged into or consolidated with the Company or any of its
     Subsidiaries; and (b) to the extent not included in clause (a), the income
     (or loss) properly allocable to a Tower or group of Towers or other assets
     accrued prior to the date such Towers or other assets are acquired by the
     Company and its Subsidiaries; provided, however, that Consolidated Net 
                                   --------  -------         
     Income shall not include:

          (1)   all amounts included in computing such net income (or loss)
     in respect of (A) the write-up of any asset on or after December 31,
     1997 or (B) the retirement of any Indebtedness or equity at less than
     face value after December 31, 1997;

          (2)   extraordinary and non-recurring gains;

          (3)   the income of any Subsidiary to the extent the payment of
     such income in the form of a Distribution or repayment of Indebtedness to
     the Company or a Wholly Owned Subsidiary is not permitted, whether on
     account of any Charter or By-law restriction, any agreement, instrument,
     deed or lease or any law, statute, judgment, decree or governmental order,
     rule or regulation applicable to such Subsidiary; and

          (4)   any after-tax gains or losses attributable to returned
     surplus assets of any Plan.

          1.2.39. "Consolidated Pro Forma Fixed Charges" means, for any future
                   ------------------------------------                       
     period, Consolidated Fixed Charges projected to be accrued by the Company
     and its Subsidiaries. For purposes of computing Consolidated Pro Forma
     Fixed Charges:

          (1)   the  amount of Financing Debt outstanding on the first day of
     such period shall be assumed to remain outstanding during the entire
     period, except to the extent required to be reduced by mandatory scheduled
     payments, reductions in revolving credit availability and other items
     included in Consolidated Fixed Charges; and

          (2)   where interest varies with a floating rate, the rate in effect
     on the first day of such period will be assumed to remain constant during
     the entire period (giving effect to any applicable Interest Rate Protection
     Agreements).

                                      -9-

 
          1.2.40. "Consolidated Pro Forma Interest Expense" means, for any 
                   --------------------------------------- 
     future period, projected Consolidated Interest Expense. For purposes of
     computing Consolidated Pro Forma Interest Expense:

          (1)   the amount of Financing Debt outstanding on the first day of
     such period shall be assumed to remain outstanding during the entire
     period, except to the extent required to be reduced by mandatory scheduled
     payments, reductions in revolving credit availability and other items
     included in Consolidated Fixed Charges; and

          (2)   where interest varies with a floating rate, the rate in effect
     on the first day of such period will be assumed to remain constant during
     the entire period (giving effect to any applicable Interest Rate Protection
     Agreements).

          1.2.41. "Consolidated Revenues" means, for any period:
                   ---------------------                        

          (1)   the net operating revenues (after reductions for discounts,
     commissions and bad debt reserves) of the Company and its Subsidiaries
     determined in accordance with GAAP on a Consolidated basis, minus
                                                                 -----

          (2)   any proceeds included in such net operating revenues from the
     sale, refinancing, condemnation or destruction of any assets.

          1.2.42. "Consolidated Site Leasing Cash Flow" means, for any period, 
                   -----------------------------------   
     the remainder of (a) Consolidated Site Leasing Revenues minus (b) the 
                                                             -----             
     cost of site leasing revenue of the Company and its Subsidiaries determined
     in accordance with GAAP on a Consolidated basis.

          1.2.43. "Consolidated Site Leasing Revenues" means, for any period:
                   ----------------------------------                        

          (1)   the net operating revenues (after reductions for discounts,
     commissions and bad debt reserves) of the Company and its Subsidiaries
     determined in accordance with GAAP on a Consolidated basis, generated from
     acquired, constructed, leased, subleased or managed Towers, minus
                                                                 -----

          (2)   any proceeds included in such net operating revenues from the
     sale, refinancing, condemnation or destruction of any assets.

          1.2.44. "Consolidated Total Debt" means, at any date, all Financing 
                   -----------------------  
     Debt of the Company and its Subsidiaries on a Consolidated basis.

          1.2.45. "Credit Documents" means:
                   ----------------        

                                     -10-

 
          (1)   this Agreement, the Notes, each Letter of Credit, each draft
     presented or accepted under a Letter of Credit, the Guarantee and Security
     Agreement, the Parent Pledge and Subordination Agreement,  the fee
     agreement contemplated by Section 5.1.2, each Estoppel and Consent Letter,
     each Mortgage, the Borrower Assumption Agreement and each Interest Rate
     Protection Agreement provided by a Lender (or an Affiliate of a Lender) to
     the Company or any of its Subsidiaries, each as from time to time in
     effect; and

          (2)   any other present or future agreement or instrument from time to
     time entered into among the Company, any of its Subsidiaries or any other
     Obligor, on one hand, and the Agent, any Letter of Credit Issuer or all the
     Lenders, on the other hand, relating to, amending or modifying this
     Agreement or any other Credit Document referred to above or which is stated
     to be a Credit Document, each as from time to time in effect.

          1.2.46. "Credit Exposure" means, at any date, the Loan and Letter of
                   ---------------                                            
     Credit Exposure, collectively.

          1.2.47. "Credit Obligations" means all present and future liabilities,
                   ------------------                                           
     obligations and Indebtedness of the Company, any of its Subsidiaries or any
     other Obligor owing to the Agent or any Lender (or any Affiliate of a
     Lender) under or in connection with this Agreement or any other Credit
     Document, including obligations in respect of principal, interest,
     reimbursement obligations under Letters of Credit and Interest Rate
     Protection Agreements provided by a Lender (or an Affiliate of a Lender),
     commitment fees, Letter of Credit fees, amounts provided for in Sections
     3.2.4, 3.5 and 9 and other fees, charges, indemnities and expenses from
     time to time owing hereunder or under any other Credit Document (all
     whether accruing before or after a Bankruptcy Default and regardless of
     whether allowed as a claim in bankruptcy or similar proceedings).

          1.2.48. "Credit Participant" is defined in Section 11.2.
                   ------------------                             

          1.2.49. "Credit Security" means all assets now or from time to time
                   ---------------                                           
     hereafter subjected to a security interest, mortgage or charge (or intended
     or required so to be subjected pursuant to the Guarantee and Security
     Agreement or any other Credit Document) to secure the payment or
     performance of any of the Credit Obligations on a pari passu basis,
     including the assets described in section 3.1 of the Guarantee and the
     Security Agreement and in section 2.1 of the Parent Pledge and
     Subordination Agreement.

          1.2.50. "Default" means any Event of Default and any event or 
                   -------     
     condition which with the passage of time or giving of notice, or both,
     would become an Event of 

                                     -11-

 
     Default and the filing against the Company, any of its Subsidiaries or any
     other Obligor of a petition commencing an involuntary case under the
     Bankruptcy Code.

          1.2.51. "Delinquency Period" is defined in Section 10.4.4.
                   ------------------                               

          1.2.52. "Delinquent Lender" is defined in Section 10.4.4.
                   -----------------                               

          1.2.53. "Delinquent Payment" is defined in Section 10.4.4.
                   ------------------                               

          1.2.54. "Designated Financing Debt" means Financing Debt incurred by
                   -------------------------     
     the Company or any of its Subsidiaries after the Effective Date other than
     Financing Debt permitted by Sections 6.6.1 (the Loan), 6.6.7 (purchase
     money Indebtedness and Capitalized Leases), 6.6.10 (intercompany
     Indebtedness) and 6.6.11 (subordinated debt).

          1.2.55. "Designated Real Property" means each real property owned or
                   ------------------------                                   
     leased by the Company or any of its Subsidiaries upon which any Tower is
     located and which must be pledged to the Agent to comply with Section
     6.20.3.

          1.2.56. "Distribution" means, with respect to the Company (or other
                   ------------                                              
     specified Person):

          (1)   the declaration or payment of any dividend or distribution on or
     in respect of any shares of any class of capital stock of or other equity
     interests in the Company (or such specified Person);

          (2)   the purchase, redemption or other retirement of any shares of
     any class of capital stock of or other equity interest in the Company (or
     such specified Person) or of options, warrants or other rights for the
     purchase of such shares, directly, indirectly through a Subsidiary or
     otherwise;

          (3)   any other distribution on or in respect of any shares of any
     class of capital stock of or equity or other beneficial interest in the
     Company (or such specified Person);

          (4)   any payment of principal or interest with respect to, or any
     purchase, redemption or defeasance of, any Financing Debt of the Company
     (or such specified Person) which by its terms or the terms of any agreement
     is subordinated to the payment of the Credit Obligations; and

          (5)   any payment, loan or advance by the Company (or such specified
     Person) to, or any other Investment by the Company (or such specified
     Person) in, the 

                                     -12-

 
     holder of any shares of any class of capital stock of or equity interest in
     the Company (or such specified Person), or any Affiliate of such holder
     (including the payment of management fees and transaction fees and
     expenses);

provided, however, that the term "Distribution" shall not include (i) dividends
- --------  -------                                                              
payable in perpetual common stock of or other similar equity interests in the
Company (or such specified Person) or (ii) payments in the ordinary course of
business in respect of (A) reasonable compensation paid to employees, officers
and directors, (B) advances and reimbursements to employees for travel expenses,
drawing accounts and similar expenditures, or (C) rent paid to, or accounts
payable for services rendered or goods sold by, non-Affiliates that own capital
stock of or other equity interests in the Company (or such specified Person).

          1.2.57. "Domestic Subsidiary" means any Subsidiary that is not a 
                   -------------------   
     Foreign Subsidiary.

          1.2.58. "Effective Date" means such date prior to June 30, 1998 agreed
                   --------------                                               
     to by the Company and the Agent as the date the amendment and restatement
     of the Original Credit Agreement as contemplated hereby becomes effective.

          1.2.59. "Environmental Laws"  means all applicable federal, state or
                   ------------------                                         
     local statutes, laws, ordinances, codes, rules, regulations and guidelines
     (including consent decrees and administrative orders) relating to public
     health and safety and protection of the environment, including the federal
     Occupational Health and Safety Act.

          1.2.60 "ERISA" means the federal Employee Retirement Income Security
                  -----                                                       
     Act of 1974.

          1.2.61. "ERISA Group Person" means the Company, any Subsidiary of the
                   ------------------                                          
     Company and any Person which is a member of the controlled group or under
     common control with the Company or any Subsidiary within the meaning of
     section 414 of the Code or section 4001(a)(14) of ERISA.

          1.2.62. "ESMR Operator" means a person licensed by the FCC to 
                   -------------
     operate an enhanced specialized mobile radio communications system, which
     system employs digital technology with a multi-site configuration that
     permits frequency re-use in specialized mobile radio frequencies.

          1.2.63. "Estoppel and Consent Letters" is defined in Section 6.20.3.
                   ----------------------------                               

                                     -13-

 
          1.2.64. "Eurodollars" means, with respect to any Lender, deposits of
                   -----------                                                
     United States Funds in a non-United States office or an international
     banking facility of such Lender.

          1.2.65. "Eurodollar Basic Rate" means, for any Eurodollar Interest
                   ---------------------                                    
     Period, the rate of interest at which Eurodollar deposits which have a term
     corresponding to such Eurodollar Interest Period are offered to the Agent
     by first class banks in the inter-bank Eurodollar market for delivery in
     immediately available funds at a Eurodollar Office on the first day of such
     Eurodollar Interest Period as determined by the Agent at approximately
     10:00 a.m. (Boston time) two Banking Days prior to the date upon which such
     Eurodollar Interest Period is to commence (which determination by the Agent
     shall, in the absence of manifest error, be conclusive).

          1.2.66. "Eurodollar Interest Period" means any period, selected as
                   --------------------------                               
     provided in Section 3.2.1, of one, two, three or six months, commencing on
     any Banking Day and ending on the corresponding date in the subsequent
     calendar month so indicated (or, if such subsequent calendar month has no
     corresponding date, on the last day of such subsequent calendar month);
     provided, however, that subject to Section 3.2.3, if any Eurodollar
     --------  -------                                                  
     Interest Period so selected would otherwise begin or end on a date which is
     not a Banking Day, such Eurodollar Interest Period shall instead begin or
     end, as the case may be, on the immediately preceding or succeeding Banking
     Day as determined by the Agent in accordance with the then current banking
     practice in the inter-bank Eurodollar market with respect to Eurodollar
     deposits at the applicable Eurodollar Office, which determination by the
     Agent shall, in the absence of manifest error, be conclusive.

          1.2.67. "Eurodollar Office" means such non-United States office or
                   -----------------                                        
     international banking facility of any Lender as the Lender may from time to
     time select.

          1.2.68. "Eurodollar Pricing Options" means the options granted 
                   --------------------------   
     pursuant to Section 3.2.1 to have the interest on any portion of the Loan
     computed on the basis of a Eurodollar Rate.

          1.2.69. "Eurodollar Rate" for any Eurodollar Interest Period means the
                   ---------------                                              
     rate, rounded upward to the nearest 1/100%, obtained by dividing (a) the
     Eurodollar Basic Rate for such Eurodollar Interest Period by (b) an amount
     equal to 1 minus the Eurodollar Reserve Rate; provided, however, that if at
                -----                              --------  -------            
     any time during such Eurodollar Interest Period the Eurodollar Reserve Rate
     applicable to any outstanding Eurodollar Pricing Option changes, the
     Eurodollar Rate for such Eurodollar Interest Period shall automatically be
     adjusted to reflect such change, effective as of the date of such change to
     the extent required by the Legal Requirement implementing such change.

                                     -14-

 
          1.2.70. "Eurodollar Reserve Rate" means the stated maximum rate
                   -----------------------                               
     (expressed as a decimal) of all reserves (including any basic,
     supplemental, marginal or emergency reserve or any reserve asset), if any,
     as from time to time in effect, required by any Legal Requirement to be
     maintained by any Lender against (a) "Eurocurrency liabilities" as
     specified in Regulation D of the Board of Governors of the Federal Reserve
     System applicable to Eurodollar Pricing Options, (b) any other category of
     liabilities that includes Eurodollar deposits by reference to which the
     interest rate on portions of the Loan subject to Eurodollar Pricing Options
     is determined, (c) the principal amount of or interest on any portion of
     the Loan subject to a Eurodollar Pricing Option or (d) any other category
     of extensions of credit, or other assets, that includes loans subject to a
     Eurodollar Pricing Option by a non-United States office of any of the
     Lenders to United States residents, in each case without the benefits of
     credits for prorations, exceptions or offsets that may be available to a
     Lender.

          1.2.71. "Event of Default" is defined in Section 8.1.
                   ----------------                            

          1.2.72. "Executive Management" means the Parent's Chief Executive
                   --------------------                                    
     Officer, Chief Financial Officer, Chief Operating Officer, Executive Vice
     President-Sales and Marketing and Senior Vice President-Corporate
     Development and General Counsel.

          1.2.73. "FAA" means the Federal Aviation Administration.
                   ---                                            

          1.2.74. "FCC" means the Federal Communications Commission.
                   ---                                              

          1.2.75. "Federal Funds Rate" means, for any day, the rate equal to the
                   ------------------                                           
     weighted average (rounded upward to the nearest 1/8%) of the rates on
     overnight federal funds transactions with members of the Federal Reserve
     System arranged by federal funds brokers, (a) as such weighted average is
     published for such day (or, if such day is not a Banking Day, for the
     immediately preceding Banking Day) by the Federal Reserve Bank of New York
     or (b) if such rate is not so published for such Banking Day, quotations
     received by the Agent from three federal funds brokers of recognized
     standing selected by the Agent.  Each determination by the Agent of the
     Federal Funds Rate shall, in the absence of manifest error, be conclusive.

          1.2.76. "Final Maturity Date" means June 29, 2005.
                   -------------------                      

          1.2.77. "Financing Debt" means each of the items described in clauses
                   --------------                                              
     (a) through (f) of the definition of the term "Indebtedness" and, without
     duplication, any Guarantees of such items.

                                      -15-

 
          1.2.78. "Financial Officer" of the Company (or other specified Person)
                   -----------------                                            
     means its chief executive officer, chief financial officer, chairman,
     president or treasurer, each of whose incumbency and signatures have been
     certified to the Agent by the secretary or other appropriate attesting
     officer of the Company (or such specified Person).

          1.2.79. "Foreign Subsidiary" means each Subsidiary that is organized
                   ------------------                                         
     under the laws of, and conducting its business primarily in a jurisdiction
     outside of, the United States of America.

          1.2.80. "Funding Liability" means (a) any Eurodollar deposit which was
                   -----------------                                            
     used (or deemed by Section 3.2.6 to have been used) to fund any portion of
     the Loan subject to a Eurodollar Pricing Option, and (b) any portion of the
     Loan subject to a Eurodollar Pricing Option funded (or deemed by Section
     3.2.6 to have been funded) with the proceeds of any such Eurodollar
     deposit.

          1.2.81. "GAAP" means generally accepted accounting principles as from
                   ----                                                        
     time to time in effect, including the statements and interpretations of the
     United States Financial Accounting Standards Board; provided, however, that
                                                         --------  -------      
     for purposes of compliance with Section 6 (other than Section 6.4) and the
     related definitions, "GAAP" means such principles as in effect on December
     31, 1997 as applied by the Company and its Subsidiaries in the preparation
     of the most recent annual statements referred to in Section 7.2.1(a), and
     consistently followed, without giving effect to any subsequent changes
     thereto.

          1.2.82. "Guarantee" means, with respect to the Company (or other
                   ---------                                              
     specified Person):

          (1)   any guarantee by the Company (or such specified Person) of the
     payment or performance of, or any contingent obligation by the Company (or
     such specified Person) in respect of, any Indebtedness or other obligation
     of any primary obligor;

          (2)   any other arrangement whereby credit is extended to a primary
     obligor on the basis of any promise or undertaking of the Company (or such
     specified Person), including any binding "comfort letter" or "keep well
     agreement" written by the Company (or such specified Person), to a creditor
     or prospective creditor of such primary obligor, to (i) pay the
     Indebtedness of such primary obligor, (ii) purchase an obligation owed by
     such primary obligor, (iii) pay for the purchase or lease of assets or
     services regardless of the actual delivery thereof or (iv) maintain the
     capital, working capital, solvency or general financial condition of such
     primary obligor;

                                      -16-

 
          (3)   any liability of the Company (or such specified Person), as a
     general partner of a partnership in respect of Indebtedness or other
     obligations of such partnership;

          (4)   any liability of the Company (or such specified Person) as a
     joint venturer of a joint venture in respect of Indebtedness or other
     obligations of such joint venture;

          (5)   any liability of the Company (or such specified Person) with
     respect to the tax liability of others as a member of a group (other than a
     group consisting solely of the Company and its Subsidiaries) that is
     consolidated for tax purposes; and

          (6)   reimbursement obligations, whether contingent or matured, of the
     Company (or such specified Person) with respect to letters of credit,
     bankers acceptances, surety bonds, other financial guarantees and Interest
     Rate Protection Agreements,

in each case whether or not any of the foregoing are reflected on the balance
sheet of the Company (or such specified Person) or in a footnote thereto;
provided, however, that the term "Guarantee" shall not include endorsements for
- --------  -------                                                              
collection or deposit in the ordinary course of business.  The amount of any
Guarantee and the amount of Indebtedness resulting from such Guarantee shall be
the maximum amount that the guarantor may become obligated to pay in respect of
the obligations (whether or not such obligations are outstanding at the time of
computation).

          1.2.83. "Guarantee and Security Agreement" is defined in Section
                   --------------------------------
     5.1.4.


          1.2.84. "Guarantor" means each Domestic Subsidiary of the Company
                   ---------
     party to, or which subsequently becomes party to, the Guarantee and
     Security Agreement as a Guarantor.

          1.2.85. "Hazardous Material" means any pollutant, toxic or hazardous
                   ------------------                                         
     material or waste, including any "hazardous substance" or "pollutant" or
     "contaminant" as defined in section 101(14) of CERCLA or any other
     Environmental Law or regulated as toxic or hazardous under RCRA or any
     other Environmental Law.

          1.2.86. "Incremental Closing Date" is defined in Section 2.2.2.
                   ------------------------                              

          1.2.87. "Incremental Commitment Notice" is defined in section 2.2.1.
                   -----------------------------                              

          1.2.88. "Incremental Conversion Date" is defined in Section 2.2.2.
                   ---------------------------                              

          1.2.89. "Incremental Facility" is defined in Section 2.2.1.
                   --------------------                              

                                      -17-

 
          1.2.90. "Incremental Revolving Loan" is defined in Section 2.2.4.
                   --------------------------                              

          1.2.91. "Incremental Revolving Notes" is defined in Section 2.2.4.
                   ---------------------------                              

          1.2.92. "Incremental Term Loan" is defined in Section 2.2.5.
                   ---------------------                              

          1.2.93. "Incremental Term Notes" is defined in Section 2.2.6.
                   ----------------------                              

          1.2.94. "Indebtedness" means all obligations, contingent or otherwise,
                   ------------                                                 
     which in accordance with GAAP are required to be classified upon the
     balance sheet of the Company (or other specified Person) as liabilities,
     but in any event including (without duplication):

          (1)   borrowed money;

          (2)   indebtedness evidenced by notes, debentures or similar
     instruments;

          (3)   Capitalized Lease Obligations;

          (4)   the deferred purchase price of assets, services or securities,
     including related noncompetition, consulting and stock repurchase
     obligations (other than ordinary trade accounts payable within six months
     after the incurrence thereof in the ordinary course of business);

          (5)   mandatory redemption or dividend rights on capital stock (or
     other equity);

          (6)   reimbursement obligations, whether contingent or matured, with
     respect to letters of credit, bankers acceptances, surety bonds, other
     financial guarantees and Interest Rate Protection Agreements (without
     duplication of other Indebtedness supported or guaranteed thereby);

          (7)   unfunded pension liabilities;

          (8)   obligations that are immediately and directly due and payable
     out of the proceeds of or production from property;

          (9)   liabilities secured by any Lien existing on property owned or
     acquired by the Company (or such specified Person), whether or not the
     liability secured thereby shall have been assumed; and

                                      -18-

 
          (10)   all Guarantees in respect of Indebtedness of others.

          1.2.95. "Indemnified Party" is defined in Section 9.2.
                   -----------------                            

          1.2.96. "Intellectual Property Security Agreements" is defined in
                   -----------------------------------------               
     Section 5.1.4.

          1.2.97. "Interest Rate Protection Agreement" means any interest rate
                   ----------------------------------                         
     swap, interest rate cap, interest rate hedge or other contractual
     arrangement that converts variable interest rates into fixed interest
     rates, fixed interest rates into variable interest rates or other similar
     arrangements.

          1.2.98. "Investment" means, with respect to the Company (or other
                   ----------                                              
     specified Person):

          (1)   any share of capital stock, partnership or other equity
     interest, evidence of Indebtedness or other security issued by any other
     Person;

          (2)   any loan, advance or extension of credit to, or contribution to
     the capital of, any other Person;

          (3)   any Guarantee of the Indebtedness of any other Person;

          (4)   any acquisition of all, or any division or similar operating
     unit of, the business of any other Person or the assets comprising such
     business, division or unit; and

          (5)   any other similar investment.

     The investments described in the foregoing clauses (a) through (e) shall be
included in the term "Investment" whether they are made or acquired by purchase,
exchange, issuance of stock or other securities, merger, reorganization or any
other method; provided, however, that the term "Investment" shall not include
              --------  -------                                              
(i) trade and customer accounts receivable for property leased, goods furnished
or services rendered in the ordinary course of business and payable on a current
basis in accordance with customary trade terms, (ii) deposits, advances or
prepayments to suppliers for property leased or licensed, goods furnished and
services rendered in the ordinary course of business, (iii) advances to
employees for relocation and travel expenses, drawing accounts and similar
expenditures, (iv) stock or other securities acquired in connection with the
satisfaction or enforcement of Indebtedness or claims due to the Company (or
such specified Person) or as security for any such Indebtedness or claim or (v)
demand deposits in banks or similar financial institutions.

                                      -19-

 
     In determining the amount of outstanding Investments:

          (A)  the amount of any Investment shall be the cost thereof minus any
                                                                      -----    
     returns of capital in cash on such Investment (determined in accordance
     with GAAP without regard to amounts realized as income on such Investment);

          (B)  the amount of any Investment in respect of a purchase described
     in clause (d) above shall include the amount of any Financing Debt assumed
     in connection with such purchase or secured by any asset acquired in such
     purchase (whether or not any Financing Debt is assumed) or for which any
     Person that becomes a Subsidiary is liable on the date on which the
     securities of such Person are acquired; and

          (C)  no Investment shall be increased as the result of an increase in
     the undistributed retained earnings of the Person in which the Investment
     was made or decreased as a result of an equity interest in the losses of
     such Person.

          1.2.99.  "Leases" means the leases with respect to real property on
                    ------
     which Towers are located.

          1.2.100. "Legal Requirement" means any present or future requirement
                    -----------------                                         
     imposed upon any of the Lenders or the Company and its Subsidiaries by any
     law, statute, rule, regulation, directive, order, decree or guideline (or
     any interpretation thereof by courts or of administrative bodies) of the
     United States of America, or any jurisdiction in which any Eurodollar
     Office is located or any state or political subdivision of any of the
     foregoing, or by any board, governmental or administrative agency, central
     bank or monetary authority of the United States of America, any
     jurisdiction in which any Eurodollar Office is located, or any political
     subdivision of any of the foregoing.  Any such law, statute, rule,
     regulation, directive, order, decree, guideline or interpretation imposed
     on any of the Lenders not having the force of law shall be deemed to be a
     Legal Requirement for purposes of Section 3 if such Lender reasonably
     believes that compliance therewith is customary commercial practice.

          1.2.101. "Lender" means each of the Persons listed as lenders on the
                    ------                                                    
     signature pages hereto, including BankBoston in its capacity as a Lender
     and such other Persons who may from time to time own a Percentage Interest
     in the Credit Obligations, but the term "Lender" shall not include any
     Credit Participant.

          1.2.102. "Lending Officer" means such individuals whom the Agent may
                    ---------------                                           
     designate in writing to the Company from time to time as the individual who
     may receive telephone requests for extensions of credit under Sections
     2.1.3, 2.2.3 and 2.3.2.

                                      -20-

 
          1.2.103. "Letter of Credit" is defined in Section 2.3.1.
                    ----------------                              

          1.2.104. "Letter of Credit Exposure" means, at any date, the sum of
                    -------------------------
     (a) the aggregate face amount of all drafts that may then or thereafter be
     presented by beneficiaries under all Letters of Credit then outstanding,
     plus (b) the aggregate face amount of all drafts that the Letter of Credit
     Issuer has previously accepted under Letters of Credit but has not paid.

          1.2.105. "Letter of Credit Issuer" means, for any Letter of Credit,
                    -----------------------                                  
     BankBoston or, in the event BankBoston does not for any reason issue a
     requested Letter of Credit, another Lender designated by the Agent to issue
     such Letter of Credit, which designation shall be made promptly by the
     Agent.

          1.2.106. "License Agreements" means any license or lease agreements
                    ------------------                                       
     between the Company or one of its Subsidiaries, on one hand, and its
     customers, on the other hand, for the licensing or leasing of space on any
     Tower.

          1.2.107. "Lien" means, with respect to the Company (or any other
                    ----                                                  
     specified Person):

          (1)   any lien, encumbrance, mortgage, pledge, charge or security
     interest of any kind upon any property or assets of the Company (or such
     specified Person), whether now owned or hereafter acquired, or upon the
     income or profits therefrom;

          (2)   the acquisition of, or the agreement to acquire, any property or
     asset upon conditional sale or subject to any other title retention
     agreement, device or arrangement (including a Capitalized Lease);

          (3)   the sale, assignment, pledge or transfer for security of any
     accounts, general intangibles or chattel paper of the Company (or such
     specified Person), with or without recourse; and

          (4)   the transfer of any tangible property or assets for the purpose
     of subjecting such items to the payment of previously outstanding
     Indebtedness in priority to payment of the general creditors of the Company
     (or such specified Person).
 
          1.2.108. "Loan" means, collectively, the Revolving Loan, the
                    ----
     Incremental Revolving Loan and the Incremental Term Loan.

          1.2.109. "Margin Stock" means "margin stock" within the meaning of
                    ------------                                            
     Regulations T, U or X of the Board of Governors of the Federal Reserve
     System.

                                      -21-

 
          1.2.110. "Material Adverse Change" means, since any specified date or
                    -----------------------                                    
     from the circumstances existing immediately prior to the happening of any
     specified event, a material adverse change in (a) the business, assets,
     financial condition, income or prospects of the Company and its
     Subsidiaries (on a Consolidated basis), whether as a result of (i) general
     economic conditions affecting the wireless telecommunications industry,
     (ii) difficulties in obtaining supplies and raw materials, (iii) fire,
     flood or other natural calamities, (iv) environmental pollution, (v)
     regulatory changes, judicial decisions, war or other governmental action or
     (vi) any other event or development, whether or not related to those
     enumerated above or (b) the ability of the Obligors to perform their
     obligations under the Credit Documents or (c) the rights and remedies of
     the Agent and the Lenders under the Credit Documents to the extent that the
     Agent and the Lenders are unable practically to realize the principal legal
     benefits of their aggregate rights and remedies under the Credit Documents.

          1.2.111. "Material Agreements" is defined in Section 7.2.2.
                    -------------------                              

          1.2.112. "Maximum Amount of Incremental Credit" is defined in Section
                    ------------------------------------                       
     2.2.1.

          1.2.113. "Maximum Amount of Revolving Credit" is defined in Section
                    ----------------------------------                       
     2.1.2.

          1.2.114. "Moody's" means Moody's Investors Service, Inc.
                    -------                                       

          1.2.115. "Mortgages" means the mortgages and the deeds of trust (and
                    ---------
     the leasehold mortgages and leasehold deeds of trust) executed by the
     Company or any of its Subsidiaries in favor of the Agent for the benefit of
     the Lenders, encumbering the real property or leaseholds upon which Towers
     are located, in substantially the form of Exhibits 6.20.3A and 6.20.3B,
     respectively.

          1.2.116. "Multiemployer Plan" means any Plan that is a "multiemployer
                    ------------------                                         
     plan" as defined in section 4001(a)(3) of ERISA.

          1.2.117. "Net Asset Sale Proceeds" means the cash proceeds of the sale
                    -----------------------
     or disposition of assets (including by way of merger), and the cash
     proceeds of any insurance payments on account of the destruction or loss of
     property, by the Company or any of its Subsidiaries after the Effective
     Date, net of (a) any Indebtedness permitted by Section 6.6.7 (Capitalized
     Leases and purchase money indebtedness) secured by assets being sold in
     such transaction required to be paid from such proceeds, (b) income taxes
     that, as estimated by the Company in good faith, will be required to be
     paid by the Company or any of its Subsidiaries in cash as a result of, and
     within 15 months after, such sale or disposition, (c) reasonable reserves
     for liabilities resulting from the

                                      -22-

 
     sale of assets and (d) all reasonable expenses of the Company or any of its
     Subsidiaries payable in connection with the sale or disposition; provided,
                                                                      --------
     however, that "Net Asset Sale Proceeds" shall not include cash proceeds:
     -------

               (1)     of asset sales permitted by Section 6.11.1,

               (2)     of mergers permitted by Section 6.11.2,

               (3)     from the sale of Tower assets that will be used to
          acquire replacement or other Tower assets within 180 days after such
          sale or disposition; provided, however, that if any amount in this
                               --------  -------
          clause (iii) is not actually used to acquire replacement or other
          Tower assets within such 180-day period, such amount shall then
          automatically become Net Asset Sale Proceeds,

               (4)     in an amount less than $100,000 for each transaction or
          series of related transactions, but not to exceed $300,000 in the
          aggregate after the Effective Date; or

               (5)   constituting insurance payments on account of the
          destruction or loss of property to the extent applied within 180 days
          after receipt to the restoration or replacement of such property.

          1.2.118. "Net Debt Proceeds" means cash proceeds of the incurrence of
                    -----------------                                          
     Designated Financing Debt by the Company or any of its Subsidiaries (net of
     reasonable out-of-pocket transaction fees and expenses).

          1.2.119. "Net Equity Proceeds" means the cash proceeds received by the
                    -------------------                                         
     Parent or any of its Subsidiaries in connection with any sale, disposition
     or issuance after the Effective Date of any shares of capital stock or
     other equity interests of the Company or any of its Subsidiaries or
     options, warrants or other purchase rights to acquire such capital stock or
     other equity interests to, or receipt of a capital contribution from, any
     Person (other than any Obligors or their officers, employees and directors)
     (net of reasonable out-of-pocket fees and expenses), excluding any such
     cash proceeds that are used by the Company or any of its Subsidiaries
     within 180 days to acquire or construct Towers; provided, however, that if
                                                     --------  -------         
     any such amount is not actually used to acquire Tower assets within such
     180-day period, such amount shall then automatically become Net Equity
     Proceeds.

          1.2.120. "Nonperforming Lender" is defined in Section 10.4.4.
                    --------------------                               

                                      -23-

 
          1.2.121. "Non-Tower Capital Expenditures" means, for any period the
                    ------------------------------                           
     remainder of (a) Capital Expenditures minus (b) amounts included in the
                                           -----                            
     foregoing clause (a) on account of Tower construction and acquisition
     costs.

          1.2.122. "Notes" means, collectively, the Revolving Notes, the
                    -----                                               
     Incremental Revolving Notes and the Incremental Term Notes.

          1.2.123. "Obligor" means the Company, the Parent, each Guarantor and
                    -------
     each other Person guaranteeing or providing collateral for the Credit
     Obligations. As of the Effective Date the only Obligors are the Company,
     the Parent and the Company's Domestic Subsidiaries.

          1.2.124. "Offering Memorandum" is defined in Section 7.2.1.
                    -------------------                              

          1.2.125. "Original Credit Agreement" is defined in Section 1.1.
                    -------------------------                            

          1.2.126. "Overdue Reimbursement Rate" means, at any date, the highest
                    --------------------------                                 
     Applicable Rate then in effect.

          1.2.127. "Parent" means SBA Communications Corporation, a Florida
                    ------                                                 
     corporation.

          1.2.128. "Parent Discount Notes" means the $269,000,000 of 12% Senior
                    ---------------------                                      
     Discount Notes due 2008 of the Parent offered pursuant to the Offering
     Memorandum, providing cash proceeds to the Parent of at least $144,500,000.

          1.2.129. "Parent Discount Notes Indenture" means the Indenture dated
                    -------------------------------                           
     March 2, 1998 between the Parent and State Street Bank and Trust Company,
     as trustee.

          1.2.130. "Parent Pledge and Subordination Agreement" is defined in
                    -----------------------------------------               
     Section 5.1.4.

          1.2.131. "Payment Date" means (a) the last Banking Day of each March,
                    ------------                                               
     June, September and December occurring after the Effective Date, (b) the
     Incremental Conversion Date and (c) the Final Maturity Date.

          1.2.132. "PBGC" means the Pension Benefit Guaranty Corporation or any
                    ----                                                       
     successor entity.

          1.2.133. "PCS A-F Block Provider" means a licensee of personal
                    ----------------------                              
     communications services frequencies who was licensed by the FCC (a) in
     auctions of 

                                      -24-

 
     the A-block, B-block, D-block, E-block or F-block frequencies concluded in
     1995, 1996 and 1997 or (b) in other auctions for which the field of bidders
     is not restricted by size or other economic factors.

          1.2.134. "PCS C-Block Provider" means (a) a licensee of 30 MHz
                    --------------------
     personal communication services frequencies who was licensed by the FCC in
     the C-block auction concluded in May 1996 and (b) any other licensee of
     personal communications services frequencies who was licensed by the FCC in
     a special auction restricted to small businesses.

          1.2.135. "Percentage Interest" means, with respect to any Lender, the
                    -------------------                                        
     Commitment of such Lender with respect to the respective portions of the
     Loan and Letter of Credit Exposure.  For purposes of determining votes or
     consents by the Lenders, the Percentage Interest of any Lender shall be
     computed as follows:  (a) at all times when no Event of Default under
     Section 8.1.1 and no Bankruptcy Default exists, the ratio that the
     respective Commitments of such Lender bears to the total Commitments of all
     Lenders as from time to time in effect and reflected in the Register, and
     (b) at all other times, the ratio that the respective amounts of the
     outstanding Loan and Letter of Credit Exposure owing to such Lender bear to
     the total outstanding Loan and Letter of Credit Exposure owing to all
     Lenders.

          1.2.136. "Performing Lender" is defined in Section 10.4.4.
                    -----------------                               

          1.2.137. "Person" means any present or future natural person or any
                    ------                                                   
     corporation, association, partnership, joint venture, limited liability,
     joint stock or other company, business trust, trust, organization, business
     or government or any governmental agency or political subdivision thereof.

          1.2.138. "PIK Interest" means any accrued interest payments on
                    ------------
     Financing Debt that are postponed, evidenced by book entry accrual or made
     through the issuance of "payment-in-kind" notes or other similar
     securities, all in accordance with the terms of such Financing Debt;
     provided, however, that in no event shall PIK Interest include payments
     --------  -------
     made with cash or Cash Equivalents.

          1.2.139. "Plan" means, at any date, any pension benefit plan subject
                    ----
     to Title IV of ERISA maintained, or to which contributions have been made
     or are required to be made, by any ERISA Group Person within six years
     prior to such date.

          1.2.140. "Pledged Towers" means, on any date, Towers with respect to
                    --------------                                            
     which the Lenders hold a perfected, first priority security interest in the
     Towers and the real property or leasehold upon which such Towers are
     located and, in the case of leaseholds, the Lenders have received an
     Estoppel and Consent Letter from the lessor.

                                      -25-

 
          1.2.141. "RCRA" means the federal Resource Conservation and Recovery
                    ----
     Act, 42 U.S.C. section 690, et seq.
                                 -- ---

          1.2.142. "Register" is defined in Section 11.1.3.
                    --------                               

          1.2.143. "Related Fund" means, with respect to any Lender that is a
                    ------------
     fund that invests in senior bank loans, any other fund that invests in
     senior bank loans and is managed by the same investment advisor as such
     Lender or by an Affiliate of such investment advisor.

          1.2.144. "Replacement Lender" is defined in Section 11.3.
                    ------------------                             

          1.2.145. "Required Lenders" means, with respect to any approval,
                    ----------------
     consent, modification, waiver or other action to be taken by the Agent or
     the Lenders under the Credit Documents which require action by the Required
     Lenders, such Lenders as own at least 60% of the Percentage Interests;
     provided, however, that with respect to any matters referred to in the
     --------  -------
     proviso to Section 15.1, Required Lenders means such Lenders as own at
     least the respective portions of the Percentage Interests required by
     Section 15.1.

          1.2.146. "Revolving Loan" is defined in Section 2.1.4.
                    --------------                              

          1.2.147. "Revolving Loan Availability Date" means the third Banking
                    --------------------------------
     Day after the Lenders first receive reports delivered in accordance with
     Section 6.4.1 or 6.4.2 that show Consolidated Adjusted EBITDA for the
     period of four consecutive fiscal quarters then ending on a date set forth
     in the table below equal to or in excess of the amount indicated in such
     table:
 
                 Fiscal Quarter Ending                  Amount
                 ---------------------                  ------
                 September 30, 1998                     $2,500,000
                 December 31, 1998                      $2,500,000
                 March 31, 1999                         $4,250,000

          1.2.148. "Revolving Notes" is defined in Section 2.1.4.
                    ---------------                              

          1.2.149. "S&P" means Standard & Poor's, a division of The McGraw Hill
                    ---                                                        
     Companies, Inc.

          1.2.150. "Securities Act" means the federal Securities Act of 1933.
                    --------------                                           

                                      -26-

 
          1.2.151. "Series A Preferred Stock" means the 4% Series A Convertible
                    ------------------------                                   
     Preferred Stock, par value $0.01 per share, of the Parent originally issued
     pursuant to the Private Placement Offering Memorandum for the Series A
     Preferred Stock dated as of February 28, 1997, as updated as of May 15,
     1997.

          1.2.152. "Series B Preferred Stock" means the 4% Series B Redeemable
                    ------------------------                                  
     Preferred Stock, par value $0.01 per share, of the Parent issuable upon
     conversion of the Series A Preferred Stock.

          1.2.153. "Series C Preferred Stock" means the 4% Series C Convertible
                    ------------------------                                   
     Preferred Stock, par value $0.01 per share, of the Parent issuable pursuant
     to the Series A Convertible Preferred Stock Purchase Agreement dated as of
     March 6, 1997 among the Parent and the purchasers named therein.

          1.2.154. "Series D Preferred Stock" means the 4% Series D Redeemable
                    ------------------------                                  
     Preferred Stock, par value $0.01 per share, of the Parent  issuable upon
     conversion of the Series C Preferred Stock.

          1.2.155. "Subsidiary" means any Person of which the Company (or other
                    ----------                                                 
     specified Person) shall at the time, directly or indirectly through one or
     more of its Subsidiaries, (a) own at least 50% of the outstanding capital
     stock (or other shares of beneficial interest) entitled to vote generally,
     (b) hold at least 50% of the partnership, joint venture or similar
     interests or (c) be a general partner or joint venturer.

          1.2.156. "Syndication Agent" means BancBoston Securities Inc.
                    -----------------                                  

          1.2.157. "Tax" means any present or future tax, levy, duty, impost,
                    ---                                                      
     deduction, withholding or other charges of whatever nature at any time
     required by any Legal Requirement (a) to be paid by any Lender or (b) to be
     withheld or deducted from any payment otherwise required hereby to be made
     to any Lender, in each case on or with respect to its obligations
     hereunder, the Loan, any payment in respect of the Credit Obligations or
     any Funding Liability not included in the foregoing; provided, however,
                                                          --------  ------- 
     that the term "Tax" shall not include taxes imposed upon or measured by the
     net income of such Lender (other than withholding taxes) or franchise taxes
     that are imposed in lieu of income taxes.

          1.2.158. "Tower Company" means a corporation or any other entity
                    -------------
     engaged primarily in the business of owning, managing, leasing and/or
     operating Towers and leasing space thereon to tenants.

          1.2.159. "Tower Threshold Date" means the date on which the Company
                    --------------------
     and its Subsidiaries first (a) own, manage or lease in their entirety at
     least 400 Towers 

                                      -27-

 
     and (b) have spent after March 1, 1998 for the construction and acquisition
     of Towers and the acquisition of Tower Companies an amount equal to the net
     proceeds received by the Parent from the issuance of the Parent Discount
     Notes minus $10,000,000.
           -----

             1.2.160. "Towers" means towers, rooftops or other structures on
                       ------
     which are affixed antennas for wireless telecommunications carriers and/or
     broadcasting services.

             1.2.161. "Tranche" means each of the Revolving Loan, the
                       -------
     Incremental Revolving Loan and the Incremental Term Loan, considered as a
     separate credit facility.

             1.2.162. "Uniform Customs and Practice" is defined in 
                       ----------------------------
     Section 2.3.7.     

             1.2.163. "United States Funds" means such coin or currency of the
                       -------------------
     United States of America as at the time shall be legal tender therein for
     the payment of public and private debts.
 
             1.2.164. "Wholly Owned Subsidiary" means any Subsidiary of which
                       -----------------------
     all of the outstanding capital stock (or other shares of beneficial
     interest) entitled to vote generally (other than directors' qualifying
     shares and, in the case of Foreign Subsidiaries, shares required by Legal
     Requirements to be held by foreign nationals) is owned by the Company (or
     other specified Person) directly, or indirectly through one or more Wholly
     Owned Subsidiaries.

 2.  THE CREDITS.
     ----------- 

     2.1.    Revolving Credit.
             ---------------- 
 
             2.1.1.   Revolving Loan.  Subject to all the terms and conditions
                      --------------
of this Agreement and so long as no Default exists, from time to time on and
after the Revolving Loan Availability Date (so long as the Company is then in
compliance with Section 6.20.3) and prior to the Final Maturity Date the Lenders
will, severally in accordance with their respective Commitments in the Revolving
Loan, make loans to the Company in such amounts as may be requested by the
Company in accordance with Section 2.1.3. The sum of the aggregate principal
amount of loans made under this Section 2.1.1 at any one time outstanding shall
in no event exceed the Maximum Amount of Revolving Credit. In no event will the
principal amount of loans at any one time outstanding made by any Lender
pursuant to this Section 2.1 exceed such Lender's Commitment with respect to the
Revolving Loan; provided, however, that loans in an aggregate amount not
                --------  -------
exceeding $1,000 may be outstanding under this Section 2.1.1 prior to the
Revolving Loan Availability Date.

                                      -28-

 
          2.1.2. Maximum Amount of Revolving Credit. The term "Maximum Amount of
                 ----------------------------------            -----------------
Revolving Credit" means the lesser of:
- ----------------                      

          (1)   the remainder of (i) (A) $25,000,000 on any date prior to the
     Tower Threshold Date; and (B) on any date thereafter, the amount specified
     for such date in the table below:
 
               Period                                 Amount
               ------                                 ------
 
          Prior to March 31, 2001                   $55,000,000
 
          On or after March 31, 2001                $52,250,000
            and prior to June 30, 2001
 
          On or after June 30, 2001                 $49,500,000
            and prior to September 30, 2001
 
          On or after September 30, 2001            $46,750,000
            and prior to December 31, 2001
 
          On or after December 31, 2001             $44,000,000
            and prior to March 31, 2002
 
          On or after March 31, 2002                $41,250,000
            and prior to June 30, 2002
 
          On or after June 30, 2002                 $38,500,000
            and prior to September 30, 2002
 
          On or after September 30, 2002            $35,750,000
            and prior to December 31, 2002
 
          On or after December 31, 2002             $33,000,000
            and prior to March 31, 2003
 
          On or after March 31, 2003                $30,250,000
            and prior to June 30, 2003
 
          On or after June 30, 2003                 $27,500,000
            and prior to September 30, 2003

                                      -29-

 
          On or after September 30, 2003            $24,750,000
            and prior to December 31, 2003
 
          On or after December 31, 2003             $22,000,000
            and prior to March 31, 2004
 
          On or after March 31, 2004                $19,250,000
            and prior to June 30, 2004
 
          On or after June 30, 2004                 $16,500,000
            and prior to September 30, 2004
 
          On or after September 30, 2004            $13,750,000
            and prior to December 31, 2004
 
          On or after December 31, 2004             $11,000,000
            and prior to the Final Maturity Date
 
          Final Maturity Date                       $0

     minus (ii) in each case to the extent allocable to the Revolving Loan in
     -----                                                                   
     accordance with Section 4.6.2, Net Asset Sale Proceeds described in Section
     4.3.2 and Net Debt Proceeds described in Section 4.3.3,

     minus (iii) after the Incremental Conversion Date to the extent allocable
     -----                                                                    
     to the Revolving Loan in accordance with Section 4.6.2, Net Equity Proceeds
     described in Section 4.3.4 and the percentage of Consolidated Excess Cash
     Flow described in Section 4.3.5 or

          (b) the amount (in an integral multiple of $1,000,000) to which the
     then applicable amount set forth in clause (a) above shall have been
     irrevocably reduced from time to time by notice from the Company to the
     Agent.  The Company shall not give a notice reducing the amount applicable
     to any period in the table above unless it shall also reduce the amounts
     applicable to all subsequent periods in such table to at least the same
     specified lower amount, so that the Maximum Amount of Revolving Credit for
     any subsequent period shall not exceed the reduced Maximum Amount of
     Revolving Credit applicable to any prior period.

          2.1.3. Borrowing Requests.  The Company may from time to time request
                 ------------------
a loan under Section 2.1.1 by providing to the Agent a notice (which may be
given by a telephone call received by a Lending Officer if promptly confirmed in
writing). Such notice must be not later than noon (Boston time) on the first
Banking Day (third Banking Day if any portion of such loan will be subject to a
Eurodollar

                                      -30-

 
     Pricing Option on the requested Closing Date) prior to the requested
     Closing Date for such loan. The notice must specify (a) the amount of the
     requested revolving loan (which shall be not less than $100,000 and an
     integral multiple of $10,000) and (b) the requested Closing Date therefor
     (which shall be a Banking Day). Upon receipt of such notice, the Agent will
     promptly inform each other Lender (by telephone or otherwise). Each such
     loan will be made at the Boston Office by depositing the amount thereof to
     the general account of the Company with the Agent. In connection with each
     such loan, the Company shall furnish to the Agent a certificate in
     substantially the form of Exhibit 5.2.1.

          2.1.4.   Revolving Notes.  The aggregate principal amount of the loans
                   ---------------                                              
     outstanding from time to time under this Section 2.1 is referred to as the
     "Revolving Loan". The Agent shall keep a record of the Revolving Loan as
      --------------
     part of the Register. The Revolving Loan shall be deemed owed to each
     Lender having a Commitment therein severally in accordance with such
     Lender's Percentage Interest therein, and all payments thereon shall be for
     the account of each Lender in accordance with its Percentage Interest
     therein. The Company's obligations to pay each Lender's Percentage Interest
     in the Revolving Loan shall be evidenced by a separate note of the Company
     in substantially the form of Exhibit 2.1.4 (the "Revolving Notes"), payable
                                                      ---------------
     to each Lender in accordance with such Lender's Percentage Interest in the
     Revolving Loan.

     2.2. Incremental Credit.
          ------------------ 

          2.2.1.   Request for Incremental Facility. Subject to all the terms of
                   --------------------------------                             
     this Agreement and so long as no Default exists, after the Revolving Loan
     Availability Date and prior to March 31, 2000, the Company may request, by
     written notice to the Agent a revolving credit loan facility (the
     "Incremental Facility") in a specified aggregate amount (the "Maximum
      --------------------                                         -------
     Amount of Incremental Credit") that does not exceed $55,000,000, and the
     ----------------------------
     proposed amortization for the Incremental Term Loan. Upon receipt of such
     request, the Agent will promptly notify each other Lender (by telephone or
     otherwise). Within 30 calendar days after receipt by the Lenders of such
     request, each Lender interested in participating in the Incremental
     Facility shall notify the Agent and the Company of its intent to
     participate and the maximum amount of its proposed Commitment with respect
     to the Incremental Facility (an "Incremental Commitment Notice"); provided,
                                      -----------------------------    --------
     however, that each Lender may participate in the Incremental Facility in
     -------
     its sole discretion, no Lender shall be deemed to have committed to
     participate in the Incremental Facility as of the date hereof, no Lender
     shall have any obligation to participate in the Incremental Facility unless
     and until it commits to do so as provided in this Section 2.2.1 and any
     Lender failing to provide an Incremental Commitment Notice within the time
     period contemplated above shall be deemed to have declined to participate
     in such Incremental Facility; and provided, further, however,
                                       --------  -------  -------

                                      -31-

 
     that the Incremental Credit Facility must be consented to in writing by the
     Required Lenders. Following receipt of such Incremental Commitment Notices,
     the Agent shall allocate the Commitments with respect to the Incremental
     Facility in accordance with the Lenders' relative requested Commitments
     therein and shall advise each Lender of the amount of such Lender's
     Commitment with respect to the Incremental Facility.

          2.2.2.    Incremental Facility. Subject to all the terms and
                    --------------------
     conditions of this Agreement and so long as no Default exists, from time to
     time on and after the establishment of the Incremental Facility in
     accordance with Section 2.3.1 (the "Incremental Closing Date") and prior to
                                         ------------------------
     the Banking Day on (or immediately prior to) the second anniversary of the
     Incremental Closing Date (but in no event later than the Final Maturity
     Date (the "Incremental Conversion Date"), any of the Lenders agreeing to
                ---------------------------
     participate in the Incremental Facility as provided in Section 2.2.1 will,
     severally in accordance with their respective Commitments therein, make
     loans to the Company with respect to the Incremental Facility as may be
     requested by the Company in accordance with Section 2.2.4. The aggregate
     principal amount of outstanding loans under the Incremental Facility shall
     in no event exceed the Maximum Amount of Incremental Credit.

          2.2.3.   Incremental Borrowing Requests.  The Company may from time to
                   ------------------------------                               
     time on or after the Incremental Closing Date and prior to the Incremental
     Conversion Date, request a loan under Section 2.2.2 by providing to the
     Agent a notice (which may be given by a telephone call received by a
     Lending Officer if promptly confirmed in writing). Such notice must be not
     later than noon (Boston time) on the first Banking Day (third Banking Day
     if any portion of such loan will be subject to a Eurodollar Pricing Option
     on the requested Closing Date) prior to the requested Closing Date for such
     loan. The notice must specify (a) the amount of the requested Incremental
     Revolving Loan (which shall be not less than $100,000 and an integral
     multiple of $10,000 and (b) the requested Closing Date therefor (which
     shall be a Banking Day). Upon receipt of such notice, the Agent will
     promptly inform each other Lender having a Commitment therein (by telephone
     or otherwise). Each such loan will be made at the Boston Office by
     depositing the amount thereof to the general account of the Company with
     the Agent. In connection with each such loan, the Company shall furnish to
     the Agent a certificate in substantially the form of Exhibit 5.2.1 and
     shall enter into any modifications of the Mortgages or other collateral
     agreements and documents reasonably requested by the Agent.

          2.2.4.   Incremental Revolving Notes.  The aggregate principal amount
                   ---------------------------
     of the loans outstanding from time to time under Section 2.2.2 is referred
     to as the "Incremental Revolving Loan". The Agent shall keep a record of
                --------------------------
     the Incremental Revolving Loan as part of the Register. The Incremental
     Revolving Loan shall be deemed owed to each Lender having a Commitment
     therein severally in accordance

                                      -32-

 
     with such Lender's Percentage Interest therein, and all payments thereon
     shall be for the account of each Lender in accordance with its Percentage
     Interest therein. The Company's obligations to pay each Lender's Percentage
     Interest in the Incremental Revolving Loan shall be evidenced by a separate
     note of the Company in substantially the form of Exhibit 2.2.4 (the
     "Incremental Revolving Notes"), payable to each Lender in accordance with
      ---------------------------
     such Lender's Percentage Interest in the Incremental Revolving Loan.

          2.2.5.   Incremental Term Loan.  Subject to all the terms and
                   ---------------------
     conditions of this Agreement and so long as no Default exists, on the
     Incremental Conversion Date the Lenders will, in accordance with their
     respective Percentage Interests in the Incremental Facility, severally lend
     to the Company as a term loan the aggregate amount of the Incremental
     Revolving Loan outstanding on such date. The aggregate principal amount of
     the loans made pursuant to this Section 2.2.5 at any one time outstanding
     is referred to as the "Incremental Term Loan". In connection with the
                            ---------------------
     Incremental Term Loan, the Company shall furnish to the Agent a certificate
     in substantially the form of Exhibit 5.2.1. The amortization schedule for
     the Incremental Term Loan shall be as agreed among the Company and the
     Required Lenders as of the Incremental Closing Date.

          2.2.6.   Incremental Term Notes.  The Incremental Term Loan shall be
                   ----------------------
     made at the Boston Office by crediting the amount of such loan to the
     Incremental Revolving Loan against delivery to the Agent of the separate
     term notes of the Company (the "Incremental Term Notes") payable to the
                                     ----------------------
     respective Lenders in accordance with their respective Percentage Interests
     in the Incremental Facility. The Incremental Term Note issued to each
     Lender shall be in substantially the form of Exhibit 2.2.6.

     2.3. Letters of Credit.
          ----------------- 

          2.3.1.   Issuance of Letters of Credit.  Subject to all the terms and
                   -----------------------------                               
     conditions of this Agreement and so long as no Default exists, from time to
     time on and after the Effective Date and prior to the Final Maturity Date,
     the Letter of Credit Issuer will issue for the account of the Company one
     or more irrevocable documentary or standby letters of credit (the "Letters
                                                                        -------
     of Credit"). Letter of Credit Exposure plus the Revolving Loan shall not at
     ---------                              ----
     any time exceed the Maximum Amount of Revolving Credit. Letter of Credit
     Exposure shall not at any time exceed $50,000,000.

          2.3.2.   Requests for Letters of Credit.  The Company may from time to
                   ------------------------------                               
     time request a Letter of Credit to be issued by providing to the Letter of
     Credit Issuer (and the Agent if the Letter of Credit Issuer is not the
     Agent) a notice (which may be given by a telephone call received by a
     Lending Officer if promptly confirmed in

                                      -33-

 
     writing). Such notice must be not less than three Banking Days prior to the
     requested Closing Date for such Letter of Credit specifying (a) the amount
     of the requested Letter of Credit, (b) the beneficiary thereof, (c) the
     requested Closing Date and (d) the principal terms of the text for such
     Letter of Credit. Each Letter of Credit will be issued by forwarding it to
     the Company or to such other Person as directed in writing by the Company.
     In connection with the issuance of any Letter of Credit, the Company shall
     furnish to the Letter of Credit Issuer (and the Agent if the Letter of
     Credit Issuer is not the Agent) a certificate in substantially the form of
     Exhibit 5.2.1 and any customary application forms required by the Letter of
     Credit Issuer. In the event of any inconsistency between such application
     forms and this Agreement, this Agreement shall govern.

          2.3.3.   Form and Expiration of Letters of Credit. Each Letter of
                   ----------------------------------------
     Credit issued under this Section 2.3 and each draft accepted or paid under
     such a Letter of Credit shall be issued, accepted or paid, as the case may
     be, by the Letter of Credit Issuer at its principal office. No Letter of
     Credit shall provide for the payment of drafts drawn thereunder, and no
     draft shall be payable, at a date which is later than the earlier of (a)
     the date 12 months after the date of issuance (which may be extended by the
     Letter of Credit Issuer) or (b) the Final Maturity Date. Each Letter of
     Credit and each draft accepted under a Letter of Credit shall be in such
     form and minimum amount, and shall contain such terms, as the Company may
     request; provided, however, that such form, amount and terms shall be
              --------  -------
     subject to the consent of the Letter of Credit Issuer, which consent shall
     not be unreasonably withheld.

          2.3.4.   Lenders' Participation in Letters of Credit.  Upon the
                   -------------------------------------------
     issuance of any Letter of Credit, a participation therein, in an amount
     equal to each Lender's Percentage Interest in the Revolving Loan, shall
     automatically be deemed granted by the Letter of Credit Issuer to each such
     Lender on the date of such issuance and such Lenders shall automatically be
     obligated, as set forth in Section 10.4, to reimburse the Letter of Credit
     Issuer to the extent of their respective Percentage Interests in the
     Revolving Loan for all obligations incurred by the Letter of Credit Issuer
     to third parties in respect of such Letter of Credit not reimbursed by the
     Company. The Letter of Credit Issuer will send to each Lender (and the
     Agent if the Letter of Credit Issuer is not the Agent) a confirmation
     regarding the participations in Letters of Credit outstanding during such
     month. The failure of any Lender to reimburse the Letter of Credit Issuer
     as required hereunder shall not relieve the Letter of Credit Issuer from
     its obligations to accept or pay any draft properly presented under such
     Letter of Credit or to issue any subsequently requested Letter of Credit.

          2.3.5.   Presentation.  The Letter of Credit Issuer may accept or pay
                   ------------
     any draft presented to it which appears on its face to be in order if such
     draft, the other required documents and any transmittal advice are
     presented to the Letter of Credit

                                      -34-

 
     Issuer and dated on or before the expiration date of the Letter of Credit
     under which such draft is drawn. Except insofar as a particular Letter of
     Credit contains express, contrary instructions, the Letter of Credit Issuer
     may honor as complying with the terms of any Letter of Credit and with this
     Agreement any drafts or other documents otherwise in order signed or issued
     by an administrator, executor, conservator, trustee in bankruptcy, debtor
     in possession, assignee for benefit of creditors, liquidator, receiver or
     other legal representative of the party authorized under such Letter of
     Credit to draw or issue such drafts or other documents.

          2.3.6.   Payment of Drafts.  At such time as a Letter of Credit Issuer
                   -----------------                                            
     makes any payment on a draft presented or accepted under a Letter of
     Credit, the Company will on demand pay to such Letter of Credit Issuer in
     immediately available funds the amount of such payment or notify the Letter
     of Credit Issuer of its intent to treat such amount as a loan under Section
     2.1.1, in which event such amount shall be considered a loan under Section
     2.1.1 and part of the Revolving Loan as if the Company had paid in full the
     amount required with respect to the Letter of Credit by borrowing such
     amount under Section 2.1.1 to the extent such amount does not cause the
     Revolving Loan to exceed the Maximum Amount of Revolving Credit. To the
     extent such amount causes the Revolving Loan to exceed the Maximum Amount
     of Revolving Credit, the Company will on demand pay to such Letter of
     Credit Issuer in immediately available funds the amount of such excess.

          2.3.7.   Uniform Customs and Practice.  The Uniform Customs and
                   ----------------------------
     Practice for Documentary Credits (1993 Revision), International Chamber of
     Commerce Publication No. 500, and any subsequent revisions thereof approved
     by a Congress of the International Chamber of Commerce and adhered to by
     the Letter of Credit Issuer (the "Uniform Customs and Practice"), shall be
                                       ----------------------------
     binding on the Company and the Letter of Credit Issuer except to the extent
     otherwise provided herein, in any Letter of Credit or in any other Credit
     Document. Anything in the Uniform Customs and Practice to the contrary
     notwithstanding:

          (1)   Neither the Company nor any beneficiary of any Letter of Credit
     shall be deemed an agent of any Letter of Credit Issuer.

          (2)   With respect to each Letter of Credit, neither the Letter of
     Credit Issuer nor its correspondents shall be responsible for or shall have
     any duty to ascertain (unless the Letter of Credit Issuer or such
     correspondent is grossly negligent or willful in failing so to ascertain):

                (1)   the genuineness of any signature;

                (2)   the validity, genuineness or legal effect of any
          endorsements;

                                      -35-

 
                (3)   delay in giving, or failure to give, notice of arrival,
          notice of refusal of documents or of discrepancies in respect of which
          any Letter of Credit Issuer refuses the documents or any other notice,
          demand or protest;

                (4)   the performance by any beneficiary under any Letter of
          Credit of such beneficiary's obligations to the Company (other than
          such beneficiary's obligation to present such items as are required to
          draw on the Letter of Credit);

                (5)   inaccuracy in any notice or demand that appears on its
          face to comply with the requirements of the Letter of Credit received
          by the Letter of Credit Issuer;

                (6)   the validity, form, sufficiency, accuracy, genuineness or
          legal effect of any instrument, draft, certificate or other document
          required by such Letter of Credit to be presented before payment of a
          draft if such instrument, draft, certificate or other document appears
          on its face to comply with the requirements of the Letter of Credit,
          or the office held by or the authority of any Person signing any of
          the same; or

                (7)   failure of any instrument to bear adequate reference to
          such Letter of Credit appearing on its face otherwise to be in order,
          or failure of any Person to note the amount of any instrument on the
          reverse of such Letter of Credit or to surrender such Letter of
          Credit.

          (3)   The occurrence of any of the events referred to in the Uniform
     Customs and Practice or in the preceding clauses of this Section 2.3.7
     shall not affect or prevent the vesting of any of the Letter of Credit
     Issuer's rights or powers hereunder or the Company's obligation to make
     reimbursement of amounts paid under any Letter of Credit or any draft
     accepted thereunder.

          (4)   The Company will promptly examine (i) each Letter of Credit (and
     any amendments thereof) sent to it by the Letter of Credit Issuer and (ii)
     all instruments and documents delivered to it from time to time by the
     Letter of Credit Issuer.  The Company will notify the Letter of Credit
     Issuer of any claim of noncompliance by notice actually received within
     three Banking Days after receipt of any of the foregoing documents, the
     Company being conclusively deemed to have waived any such claim against
     such Letter of Credit Issuer and its correspondents unless such notice is
     given.  The Letter of Credit Issuer shall have no obligation or
     responsibility to send any such Letter of Credit or any such instrument or
     document to the Company.

          (5)   In the event of any conflict between the provisions of this
     Agreement and the Uniform Customs and Practice, the provisions of this
     Agreement shall govern.

                                      -36-

 
          2.3.8.   Subrogation.  Upon any payment by a Letter of Credit Issuer
                   -----------                                                
     under any Letter of Credit and until the reimbursement of such Letter of
     Credit Issuer by the Company with respect to such payment, the Letter of
     Credit Issuer shall be entitled to be subrogated to, and to acquire and
     retain, the rights which the Person to whom such payment is made may have
     against the Company, all for the benefit of the Lenders. The Company will
     take such action as the Letter of Credit Issuer may reasonably request,
     including requiring the beneficiary of any Letter of Credit to execute such
     documents as the Letter of Credit Issuer may reasonably request, to assure
     and confirm to the Letter of Credit Issuer such subrogation and such
     rights, including the rights, if any, of the beneficiary to whom such
     payment is made in accounts receivable, inventory and other properties and
     assets of any Obligor.

          2.3.9.   Modification, Consent, etc. If the Company requests or
                   --------------------------
     consents in writing to any modification or extension of any Letter of
     Credit, or waives in writing any failure of any draft, certificate or other
     document to comply with the terms of such Letter of Credit, and if the
     Letter of Credit Issuer consents thereto, the Letter of Credit Issuer shall
     be entitled to rely on such written request, consent or waiver. This
     Agreement shall be binding upon the Company with respect to such Letter of
     Credit as so modified or extended, and with respect to any action taken or
     omitted by such Letter of Credit Issuer pursuant to any such written
     request, consent or waiver.

     2.4. Application of Proceeds.
          ----------------------- 

          2.4.1.   Revolving Loan.  Subject to Section 2.4.4, the Company will
                   --------------                                             
     apply the proceeds of the Revolving Loan for the acquisition of Towers and
     Tower Companies and construction of Towers, working capital and other
     lawful corporate purposes of the Company and its Subsidiaries.

         2.4.2.    Incremental Facility.  The Company will apply the proceeds of
                   --------------------                                         
     the Incremental Revolving Loan for the acquisition of Towers and Tower
     Companies and construction of Towers, working capital and other lawful
     corporate purposes of the Company and its Subsidiaries. The Company will
     apply the proceeds of the Incremental Term Loan solely to repay in full the
     Incremental Revolving Loan.

         2.4.3.    Letters of Credit.  Letters of Credit shall be issued only to
                   -----------------                                            
     provide credit support for its payment or performance obligations related
     to the acquisition of Towers and Tower Companies or construction of Towers
     or for such other lawful corporate purposes as the Company has requested in
     writing and to which the Letter of Credit Issuer agrees.

                                      -37-

 
          2.4.4.   Specifically Prohibited Applications.  The Company will not,
                   ------------------------------------                        
     directly or indirectly, apply any part of the proceeds of any extension of
     credit made pursuant to the Credit Documents (a) to purchase or to carry
     Margin Stock or (b) to engage in any transaction prohibited by Legal
     Requirements applicable to the Lenders or by the Credit Documents.

     2.5.  Nature of Obligations of Lenders to Make Extensions of Credit.  The
           -------------------------------------------------------------      
Lenders' obligations to extend credit under this Agreement are several and are
not joint or joint and several.  If on any Closing Date any Lender shall fail to
perform its obligations under this Agreement, the aggregate amount of
Commitments to make the extensions of credit under this Agreement shall be
reduced by the amount of unborrowed Commitment of the Lender so failing to
perform and the Percentage Interests shall be appropriately adjusted.  Lenders
that have not failed to perform their obligations to make the extensions of
credit contemplated by Section 2 may, if any such Lender so desires, assume, in
such proportions as such Lenders may agree, the obligations of any Lender who
has so failed and the Percentage Interests shall be appropriately adjusted.  The
failure of any Lender to perform its obligations under this Agreement, including
its obligation to make the extensions of credit contemplated by Section 2, shall
not relieve any other Lender from its obligations under this Agreement,
including its obligation to make the extensions of credit contemplated by
Section 2, or relieve any Lender (including the Lender who failed to perform its
obligation) of its obligations to extend credit contemplated by Section 2 as
part of any subsequent extension of credit.  A waiver by the Company or any of
its Subsidiaries of the performance by any Lender of any of its obligations
under the Credit Documents, including its obligation to make any extensions of
credit contemplated by Section 2, shall not constitute a waiver by the Company
or any of its Subsidiaries of any obligations of any other Lender of its
obligations under the Credit Documents, including its obligations to make the
extensions of credit contemplated by Section 2, or relieve the Lender who failed
to fulfill its obligations of its obligations with respect to any subsequent
request for an extension of credit under the Credit Documents.

                                      -38-

 
3.   INTEREST; EURODOLLAR PRICING OPTIONS; FEES.
     ------------------------------------------ 

     3.1. Interest.  The Loan shall accrue and bear interest at a rate per annum
          --------                                                              
which shall at all times equal the Applicable Rate.  Prior to any stated or
accelerated maturity of the Loan, the Company will, on each Payment Date, pay
the accrued and unpaid interest on the portion of the Loan which was not subject
to a Eurodollar Pricing Option.  On the last day of each Eurodollar Interest
Period or on any earlier termination of any Eurodollar Pricing Option, the
Company will pay the accrued and unpaid interest on the portion of the Loan
which was subject to the Eurodollar Pricing Option which expired or terminated
on such date.  In the case of any Eurodollar Interest Period longer than three
months, the Company will also pay the accrued and unpaid interest on the portion
of the Loan subject to the Eurodollar Pricing Option having such Eurodollar
Interest Period at three-month intervals, the first such payment to be made on
the last Banking Day of the three-month period which begins on the first day of
such Eurodollar Interest Period.  On the stated or any accelerated maturity of
the Loan, the Company will pay all accrued and unpaid interest on the Loan,
including any accrued and unpaid interest on any portion of the Loan which is
subject to a Eurodollar Pricing Option.  Upon the occurrence and during the
continuance of an Event of Default, the Lenders may require accrued interest to
be payable on demand or at regular intervals more frequent than each Payment
Date.  All payments of interest hereunder shall be made to the Agent for the
account of each Lender in accordance with such Lender's Percentage Interest.

     3.2. Eurodollar Pricing Options.
          -------------------------- 

          3.2.1.   Election of Eurodollar Pricing Options.  Subject to all of
                   --------------------------------------
the terms and conditions hereof and so long as no Default exists, the Company
may from time to time, by irrevocable notice (which notice may be given by a
telephone call received by a Lending Officer if promptly confirmed in writing)
to the Agent actually received by noon (Boston time) not less than three Banking
Days prior to the commencement of the Eurodollar Interest Period selected in
such notice, elect to have such portion of the Loan as the Company may specify
in such notice accrue and bear interest during the Eurodollar Interest Period so
selected at the Applicable Rate computed on the basis of the Eurodollar Rate. In
the event the Company at any time does not elect a Eurodollar Pricing Option
under this Section 3.2.1 for any portion of the Loan (upon termination of a
Eurodollar Pricing Option or otherwise), then such portion of the Loan will
accrue and bear interest at the Applicable Rate based on the Base Rate. A single
Eurodollar Option may include any portion of the Revolving Loan, Incremental
Revolving Loan or Incremental Term Loan designated by the Company in the notice
referred to above. No election of a Eurodollar Pricing Option shall become
effective:

          (1)   if, prior to the commencement of any such Eurodollar Interest
     Period, the Agent determines and notifies the Company (which notice may be
     given by a 

                                      -39-

 
     telephone call received by a Lending Officer if promptly confirmed in
     writing) that (i) the electing or granting of the Eurodollar Pricing Option
     in question would violate a Legal Requirement, (ii) Eurodollar deposits in
     an amount comparable to the principal amount of the Loan as to which such
     Eurodollar Pricing Option has been elected and which have a term
     corresponding to the proposed Eurodollar Interest Period are not readily
     available in the inter-bank Eurodollar market, or (iii) by reason of
     circumstances affecting the inter-bank Eurodollar market, adequate and
     reasonable methods do not exist for ascertaining the interest rate
     applicable to such deposits for the proposed Eurodollar Interest Period; or

          (2)   if the Required Lenders shall have advised the Agent by
     telephone or otherwise at or prior to noon (Boston time) on the second
     Banking Day prior to the commencement of such proposed Eurodollar Interest
     Period (and shall have subsequently confirmed in writing) that, after
     reasonable efforts to determine the availability of such Eurodollar
     deposits, the Required Lenders reasonably anticipate that Eurodollar
     deposits in an amount equal to the Percentage Interest of the Required
     Lenders in the portion of the Loan as to which such Eurodollar Pricing
     Option has been elected and which have a term corresponding to the
     Eurodollar Interest Period in question will not be offered in the
     Eurodollar market to the Required Lenders at a rate of interest that does
     not exceed the anticipated Eurodollar Basic Rate and the Agent shall have
     notified the Company thereof (which notice may be given by a telephone call
     received by a Financial Officer if promptly confirmed in writing).

          3.2.2.   Notice to Lenders and Company.  The Agent will promptly
                   -----------------------------
     inform each Lender (by telephone or otherwise) of each notice received by
     it from the Company pursuant to Section 3.2.1 and of the Eurodollar
     Interest Period specified in such notice. Upon determination by the Agent
     of the Eurodollar Rate for such Eurodollar Interest Period or in the event
     such election shall not become effective, the Agent will promptly notify
     the Company and each Lender (by telephone or otherwise) of the Eurodollar
     Rate so determined or why such election did not become effective, as the
     case may be.

          3.2.3.   Selection of Eurodollar Interest Periods.  Eurodollar
                   ----------------------------------------
     Interest Periods shall be selected so that:

          (1)   the minimum portion of the Loan subject to any Eurodollar
     Pricing Option shall be $500,000 and an integral multiple of $100,000;

          (2)   no more than 12 Eurodollar Pricing Options shall be outstanding
     at any one time;

                                      -40-

 
          (3)   a portion of the Loan equal to or greater than the amount of the
     next mandatory prepayment required by Section 4.2 shall not be subject to a
     Eurodollar Pricing Option on the date such mandatory prepayment is required
     to be made; and

          (4)   no Eurodollar Interest Period shall expire later than the Final
     Maturity Date.

          3.2.4.   Additional Interest.  If any portion of the Loan subject to a
                   -------------------                                          
     Eurodollar Pricing Option is repaid, or any Eurodollar Pricing Option is
     terminated for any reason (including acceleration of maturity), on a date
     which is prior to the last Banking Day of the Eurodollar Interest Period
     applicable to such Eurodollar Pricing Option, the Company will pay to the
     Agent for the account of each Lender in accordance with such Lender's
     Percentage Interest, in addition to any amounts of interest otherwise
     payable hereunder, an amount equal to the present value (calculated in
     accordance with this Section 3.2.4) of interest for the unexpired portion
     of such Eurodollar Interest Period on the portion of the Loan so repaid, or
     as to which a Eurodollar Pricing Option was so terminated, at a per annum
     rate equal to the excess, if any, of (a) the rate applicable to such
     Eurodollar Pricing Option minus (b) the rate of interest obtainable by the
                               -----
     Agent upon the purchase of debt securities customarily issued by the
     Treasury of the United States of America which have a maturity date
     approximating the last Banking Day of such Eurodollar Interest Period. The
     present value of such additional interest shall be calculated by
     discounting the amount of such interest for each day in the unexpired
     portion of such Eurodollar Interest Period from such day to the date of
     such repayment or termination at a per annum interest rate equal to the
     interest rate determined pursuant to clause (b) of the preceding sentence,
     and by adding all such amounts for all such days during such period. The
     determination by the Agent of such amount of interest shall, in the absence
     of manifest error, be conclusive. For purposes of this Section 3.2.4, if
     any portion of the Loan which was to have been subject to a Eurodollar
     Pricing Option is not outstanding on the first day of the Eurodollar
     Interest Period applicable to such Eurodollar Pricing Option other than for
     reasons described in Section 3.2.1 or the failure of one or more Lenders to
     fulfill their obligations hereunder, the Company shall be deemed to have
     terminated such Eurodollar Pricing Option.

          3.2.5.   Violation of Legal Requirements.  If any Legal Requirement
                   -------------------------------
     shall prevent any Lender from funding or maintaining through the purchase
     of deposits in the interbank Eurodollar market any portion of the Loan
     subject to a Eurodollar Pricing Option or otherwise from giving effect to
     such Lender's obligations as contemplated by Section 3.2, (a) the Agent may
     by notice to the Company terminate all of the affected Eurodollar Pricing
     Options, (b) the portion of the Loan subject to such terminated Eurodollar
     Pricing Options shall immediately bear interest thereafter at the
     Applicable 

                                      -41-

 
     Rate computed on the basis of the Base Rate and (c) the Company shall make
     any payment required by Section 3.2.4.

          3.2.6.   Funding Procedure.  The Lenders may fund any portion of the
                   -----------------
     Loan subject to a Eurodollar Pricing Option out of any funds available to
     the Lenders. Regardless of the source of the funds actually used by any of
     the Lenders to fund any portion of the Loan subject to a Eurodollar Pricing
     Option, however, all amounts payable hereunder, including the interest rate
     applicable to any such portion of the Loan and the amounts payable under
     Sections 3.2.4 and 3.5, shall be computed as if each Lender had actually
     funded such Lender's Percentage Interest in such portion of the Loan
     through the purchase of deposits in such amount of the type by which the
     Eurodollar Basic Rate was determined with a maturity the same as the
     applicable Eurodollar Interest Period relating thereto and through the
     transfer of such deposits from an office of the Lender having the same
     location as the applicable Eurodollar Office to one of such Lender's
     offices in the United States of America.

     3.3. Commitment Fees.
          --------------- 

          3.3.1.   Revolving Loan.  In consideration of the Lenders' commitments
                   --------------
     to make the extensions of credit provided for in Section 2.1, while such
     commitments are outstanding, the Company will pay to the Agent for the
     account of the Lenders in accordance with the Lenders' respective
     Commitments in the Revolving Loan, on each Payment Date and on the Final
     Maturity Date, an amount equal to interest computed at the Commitment Fee
     Rate on the amount by which (a) the average daily Maximum Amount of
     Revolving Credit during the three-month period or portion thereof ending on
     such Payment Date exceeded (b) the average daily Revolving Loan during such
     period or portion thereof; provided, however, that with respect to the
                                --------  -------
     first Payment Date after the date hereof such period shall be calculated
     from the date hereof to such Payment Date.

          3.3.2.   Incremental Revolving Loan.  In consideration of the Lenders'
                   --------------------------                                   
     commitments to make the extensions of credit provided for in Section 2.2,
     while such commitments are outstanding, the Company will pay to the Agent
     for the account of the Lenders in accordance with the Lenders' respective
     Commitments in the Incremental Revolving Loan, on each Payment Date after
     the Incremental Closing Date and on the Incremental Conversion Date, an
     amount equal to interest computed at the Commitment Fee Rate on the amount
     by which (a) the average daily Maximum Amount of Incremental Credit during
     the three-month period or portion thereof ending on such Payment Date
     exceeded (b) the average daily Incremental Revolving Loan during such
     period or portion thereof.

                                      -42-

 
     3.4. Letter of Credit Fees.  The Company will pay to the Agent for the
          ---------------------                                            
account of each of the Lenders, in accordance with the Lenders' respective
Percentage Interests, on each Payment Date, a Letter of Credit fee equal to
interest at a rate per annum equal to the Applicable Margin indicated for the
Eurodollar Rate on the average daily Letter of Credit Exposure during the three-
month period or portion thereof ending on such Payment Date. The Company will
pay to the Letter of Credit Issuer customary service charges and expenses for
its services in connection with the Letters of Credit at the times and in the
amounts from time to time in effect in accordance with its general rate
structure, including fees and expenses relating to issuance, amendment,
negotiation, cancellation and similar operations.

     3.5. Changes in Circumstances; Yield Protection.
          ------------------------------------------ 

          3.5.1.   Reserve Requirements, etc.  If any Legal Requirement shall
                   -------------------------
     (a) impose, modify, increase or deem applicable any insurance assessment,
     reserve, special deposit or similar requirement against any Funding
     Liability or the Letters of Credit, (b) impose, modify, increase or deem
     applicable any other requirement or condition with respect to any Funding
     Liability or the Letters of Credit, or (c) change the basis of taxation of
     Funding Liabilities or payments in respect of any Letter of Credit (other
     than changes in the rate of taxes measured by the overall net income of
     such Lender) and the effect of any of the foregoing shall be to increase
     the cost to any Lender of issuing, making, funding or maintaining its
     respective Percentage Interest in any portion of the Loan subject to a
     Eurodollar Pricing Option or any Letter of Credit, to reduce the amounts
     received or receivable by such Lender under this Agreement or to require
     such Lender to make any payment or forego any amounts otherwise payable to
     such Lender under this Agreement (other than any Tax or any reserves that
     are included in computing the Eurodollar Reserve Rate), then such Lender
     may claim compensation from the Company under Section 3.5.5.

          3.5.2.   Taxes.  All payments of the Credit Obligations shall be made
                   -----                                                       
     without set-off or counterclaim and free and clear of any deductions,
     including deductions for Taxes, unless the Company is required by law to
     make such deductions. If (a) any Lender shall be subject to any Tax with
     respect to any payment of the Credit Obligations or its obligations
     hereunder or (b) the Company shall be required to withhold or deduct any
     Tax on any payment on the Credit Obligations, then such Lender may claim
     compensation from the Company under Section 3.5.5 to the extent such Lender
     is then in compliance with any applicable requirements of Section 13.
     Whenever Taxes must be withheld by the Company with respect to any payments
     of the Credit Obligations, the Company shall promptly furnish to the Agent
     for the account of the applicable Lender official receipts (to the extent
     that the relevant governmental authority delivers such receipts) evidencing
     payment of any such Taxes so withheld. If the Company fails to pay any such
     Taxes when due or fails to remit to the Agent for the account of the
     applicable Lender the required receipts evidencing payment of any such

                                      -43-

 
     Taxes so withheld or deducted, following a written request from the Agent
     with respect thereto, the Company shall indemnify the affected Lender for
     any incremental Taxes and interest or penalties that may become payable by
     such Lender as a result of any such failure. In the event any Lender
     receives a refund of any Taxes for which it has received payment from the
     Company under this Section 3.5.2, such Lender shall promptly pay the amount
     of such refund to the Company, together with any interest thereon actually
     earned by such Lender.

          3.5.3.   Capital Adequacy.  If any Lender shall determine that
                   ----------------
     compliance by such Lender with any Legal Requirement regarding capital
     adequacy of banks or bank holding companies has or would have the effect of
     reducing the rate of return on the capital of such Lender and its
     Affiliates as a consequence of such Lender's commitment to make the
     extensions of credit contemplated hereby, or such Lender's maintenance of
     the extensions of credit contemplated hereby, to a level below that which
     such Lender could have achieved but for such compliance (taking into
     consideration the policies of such Lender and its Affiliates with respect
     to capital adequacy immediately before such compliance and assuming that
     the capital of such Lender and its Affiliates was fully utilized prior to
     such compliance) by an amount deemed by such Lender to be material, then
     such Lender may claim compensation from the Company under Section 3.5.5.

          3.5.4.   Regulatory Changes.  If any Lender shall determine that (a)
                   ------------------
     any change in any Legal Requirement (including any new Legal Requirement)
     after the date hereof shall directly or indirectly (i) reduce the amount of
     any sum received or receivable by such Lender with respect to the Loan or
     the Letters of Credit or the return to be earned by such Lender on the Loan
     or the Letters of Credit, (ii) impose a cost on such Lender or any
     Affiliate of such Lender that is attributable to the making or maintaining
     of, or such Lender's commitment to make, its portion of the Loan or the
     Letters of Credit, or (iii) require such Lender or any Affiliate of such
     Lender to make any payment on, or calculated by reference to, the gross
     amount of any amount received by such Lender under any Credit Document
     (other than Taxes or income or franchise taxes), and (b) such reduction,
     increased cost or payment shall not be fully compensated for by an
     adjustment in the Applicable Rate or the Letter of Credit fees, then such
     Lender may claim compensation from the Company under Section 3.5.5.

          3.5.5.   Compensation Claims.  Within 30 days after the receipt by the
                   -------------------                                          
     Company of a certificate from any Lender setting forth why it is claiming
     compensation under this Section 3.5 and computations (in reasonable detail)
     of the amount thereof, the Company shall pay to such Lender such additional
     amounts as such Lender sets forth in such certificate as sufficient fully
     to compensate it on account of the foregoing provisions of this Section
     3.5, together with interest on such amount from the 15th day after receipt
     of such certificate until payment in full thereof at the Overdue

                                      -44-

 
     Reimbursement Rate. The determination by such Lender of the amount to be
     paid to it and the basis for computation thereof hereunder shall be
     conclusive so long as (a) such determination is made in good faith, (b) no
     manifest error appears therein and (c) the Lender uses reasonable averaging
     and attribution methods. The Company shall be entitled to replace any such
     Lender in accordance with Section 11.3. Notwithstanding any provision to
     the contrary contained in any Credit Document, no Lender shall be entitled
     to compensation hereunder in the event any reduction, increased costs,
     payment or the like which serves as the basis for a claim hereunder is
     fully compensated for by an adjustment in the Applicable Rate or the Letter
     of Credit fees.

          3.5.6.   Mitigation.  Each Lender shall take such commercially
                   ----------
     reasonable steps as it may determine are not disadvantageous to it,
     including changing lending offices to the extent feasible, in order to
     reduce amounts otherwise payable by the Company to such Lender pursuant to
     Sections 3.2.4 and 3.5 or to make Eurodollar Pricing Options available
     under Sections 3.2.1 and 3.2.5. In addition, the Company shall not be
     responsible for costs (a) under Section 3.5 arising more than 90 days prior
     to receipt by the Company of the certificate from the affected Lender
     pursuant to such Section 3.5 or (b) under Section 3.2.4 arising from the
     termination of Eurodollar Pricing Options more than 90 days prior to the
     demand by the Agent for payment under Section 3.2.4.

     3.6. Computations of Interest and Fees.  For purposes of this Agreement,
          ---------------------------------                                  
interest, commitment fees and Letter of Credit fees (and any other amount
expressed as interest or such fees) shall be computed on the basis of a 365-day
year for actual days elapsed; provided, however, that interest based on the
                              --------  -------                            
Eurodollar Rate shall be computed on the basis of a 360-day year for actual days
elapsed.  If any payment required by this Agreement becomes due on any day that
is not a Banking Day, such payment shall, except as otherwise provided in the
Eurodollar Interest Period, be made on the next succeeding Banking Day.  If the
due date for any payment of principal is extended as a result of the immediately
preceding sentence, interest shall be payable for the time during which payment
is extended at the Applicable Rate.

4.   PAYMENT.
     ------- 

     4.1. Payment at Maturity.  On the Final Maturity Date or any accelerated
          -------------------                                                
maturity of the Loan, the Company will pay to the Agent an amount equal to the
Loan then due, together with all accrued and unpaid interest and fees with
respect thereto and all other Credit Obligations then outstanding.

     4.2. Scheduled Required Prepayments.  On each Payment Date after the
          ------------------------------                                 
Incremental Conversion Date, the Company will pay to the Agent as a prepayment
of the Incremental Term Loan the lesser of (a) an amount equal to the percentage
of the Incremental Term Loan outstanding at the opening of business on the
Incremental Conversion Date as agreed among 

                                      -45-

 
the Company and the Required Lenders as of the Incremental Closing Date and (b)
the amount of the Incremental Term Loan then outstanding.

     4.3. Contingent Required Prepayments.
          ------------------------------- 

          4.3.1.   Excess Credit Exposure.  If at any time the Revolving Loan or
                   ----------------------                                       
     the Incremental Revolving Loan, as the case may be, exceeds the limits set
     forth in Section 2.1 or Section 2.2, respectively, the Company shall within
     one Banking Day pay the amount of such excess to the Agent as a prepayment
     of the Revolving Loan or the Incremental Revolving Loan, as appropriate. If
     at any time the Letter of Credit Exposure exceeds the limits set forth in
     Section 2.3, the Company shall within one Banking Day pay the amount of
     such excess to the Agent to be applied as provided in Section 4.5.

          4.3.2.   Net Asset Sale Proceeds.  Within five days prior to the sale
                   -----------------------
     or other disposition of any assets by the Company or its Subsidiaries that
     would result in Net Asset Sale Proceeds, the Company shall provide written
     notice to the Lenders of the anticipated closing date for such asset sale
     or disposition and the amount of such Net Asset Sale Proceeds. Upon receipt
     of Net Asset Sale Proceeds by the Company or any of its Subsidiaries, the
     Company shall within one Banking Day pay to the Agent as a prepayment of
     the Loan to be applied as provided in Section 4.6.2 the lesser of (a) the
     amount of such Net Asset Sale Proceeds or (b) the amount of the Loan.

          4.3.3.   Net Debt Proceeds.  Within five days prior to the incurrence
                   -----------------
     of Designated Financing Debt by the Company or any of its Subsidiaries, the
     Company shall provide written notice to the Lenders of the anticipated
     closing date for such Designated Financing Debt and the amount of the Net
     Debt Proceeds. Within one Banking Day after the incurrence of Designated
     Financing Debt by the Company or any of its Subsidiaries, the Company shall
     pay to the Agent as a prepayment of the Loan to be applied as provided in
     Section 4.6.2 the lesser of (a) the amount of such Net Debt Proceeds or (b)
     the amount of the Loan.

          4.3.4.   Net Equity Proceeds.  Within five days prior to the 
                   -------------------
     consummation of any transaction on or after the Incremental Conversion Date
     that would result in Net Equity Proceeds, the Company shall provide written
     notice to the Lenders of the anticipated closing date for such transaction
     and the amount of the Net Equity Proceeds. Within one Banking Day after the
     receipt of Net Equity Proceeds by any Obligor on or after the Incremental
     Conversion Date, the Company shall pay to the Agent as a prepayment of the
     Loan to be applied as provided in Section 4.6.2 the lesser of (a) the
     amount of such Net Equity Proceeds or (b) the amount of the Loan.

                                      -46-

 
          4.3.5.   Excess Cash Flow.  Within 120 days after the end of each 
                   ----------------
     fiscal year of the Company, but only if the Incremental Conversion Date has
     occurred prior to such 120th day, the Company shall pay to the Agent as a
     prepayment of the Loan, to be applied as provided in Section 4.6.2, an
     amount equal to the lesser of (a) 50% of Consolidated Excess Cash Flow for
     its then most recently completed fiscal year or (b) the amount of the Loan.

     4.4. Voluntary Prepayments.  In addition to the prepayments required by
          ---------------------                                             
Sections 4.2 and 4.3, the Company may from time to time prepay all or any
portion of the Loan (in a minimum amount of $100,000 and an integral multiple of
$10,000, or such lesser amount as is then outstanding), without premium or
penalty of any type (except as provided in Section 3.2.4 with respect to the
early termination of Eurodollar Pricing Options).  The Company shall give the
Agent at least one Banking Day prior notice of its intention to prepay the
Revolving Loan or the Incremental Revolving Loan under this Section 4.4,
specifying the date of payment and the total amount of the Revolving Loan or the
Incremental Revolving Loan to be paid on such date.  The Company shall give the
Agent at least three Banking Day's prior notice of its intention to prepay the
Incremental Term Loan under this Section 4.4, specifying the date of payment,
the total amount of the Incremental Term Loan to be paid on such date and the
amount of interest to be paid with such prepayment.

     4.5. Letters of Credit.  If on the Final Maturity Date or any accelerated
          -----------------                                                   
maturity of the Credit Obligations the Lenders shall be obligated in respect of
a Letter of Credit or a draft accepted under a Letter of Credit, the Company
will either:

               (1)   prepay such obligation by depositing cash with the Agent,
               or

               (2)   deliver to the Agent a standby letter of credit
               (designating the Agent as beneficiary and issued by a bank and on
               terms reasonably acceptable to the Agent),

in each case in an amount equal to the portion of the then Letter of Credit
Exposure issued for the account of the Company.  Any such cash so deposited and
the cash proceeds of any draw under any standby Letter of Credit so furnished,
including any interest thereon, shall be returned by the Agent to the Company
only when, and to the extent that, the amount of such cash held by the Agent
exceeds the Letter of Credit Exposure at such time and no Default then exists;
provided, however, that if an Event of Default occurs and the Credit Obligations
- --------  -------                                                               
become or are declared immediately due and payable, the Agent may apply such
cash, including any interest thereon, to the payment of any of the Credit
Obligations as provided in section 3.5.6 of the Guarantee and Security
Agreement.

     4.6.  Reborrowing; Application of Payments, etc.
           ------------------------------------------

                                      -47-

 
           4.6.1.   Reborrowing.  The amounts of the Revolving Loan prepaid 
                    -----------
pursuant to Section 4.4 may be reborrowed from time to time prior to the Final
Maturity Date in accordance with Section 2.1, subject to the limits set forth
therein. The amounts of the Incremental Revolving Loan prepaid pursuant to
Section 4.4 may be reborrowed from time to time prior to the Incremental
Conversion Date in accordance with Section 2.2, subject to the limits set forth
therein. No portion of the Incremental Term Loan prepaid hereunder may be
reborrowed.

           4.6.2.   Order of Application.  Any prepayment of the Loan pursuant
                    --------------------
to Sections 4.3.2, 4.3.3, 4.3.4, 4.3.5 or 4.4 shall be applied first to the
Incremental Revolving Loan or Incremental Term Loan (whichever, if any, is then
outstanding), with any balance to the Revolving Loan (and to the permanent
reduction of the Maximum Amount of Revolving Credit and the corresponding
Revolving Loan Commitments whether or not any Revolving Loan is then
outstanding).  Prepayments of the Incremental Term Loan pursuant to Sections 4.3
or 4.4 shall be applied in the inverse order of the maturity thereof so that no
partial prepayment of the Incremental Term Loan shall affect the obligation of
the Company to make the prepayments required by Section 4.2.  Subject to the
foregoing, any prepayment of the Loan shall be applied first to the portion of
the Loan then subject to Eurodollar Pricing Options, then the balance of any
such prepayment shall be applied to the portion of the Loan not then subject to
Eurodollar Pricing Options, in chronological order of the respective maturities
thereof (or as the Company may otherwise specify in writing), together with any
payments required by Section 3.2.4.

           4.6.3.   Payment with Accrued Interest, etc.  Upon all prepayments 
                    ----------------------------------
of the Incremental Term Loan, the Company shall pay to the Agent the principal
amount to be prepaid, together with unpaid interest in respect thereof accrued
to the date of prepayment. Notice of prepayment having been given in accordance
with Section 4.4, and whether or not notice is given of prepayments pursuant to
Sections 4.2 and 4.3, the amount specified to be prepaid shall become due and
payable on the date specified for prepayment.

           4.6.4.   Payments for Lenders.  All payments of principal hereunder
                    --------------------
shall be made to the Agent for the account of the Lenders in accordance with the
Lenders' respective Percentage Interests.

 5.  CONDITIONS TO EXTENDING CREDIT.
     ------------------------------ 

     5.1. Conditions on Effective Date.  The obligations of the Lenders to make
          ----------------------------                                         
any extension of credit pursuant to Section 2 shall be subject to the
satisfaction, on or before the Effective Date, of the conditions set forth in
this Section 5.1 as well as the further conditions in Section 5.2.  If the
conditions set forth in this Section 5.1 are not met on or prior to the

                                      -48-

 
Effective Date, the Lenders shall have no obligation to make any extensions of
credit hereunder.

          5.1.1.   Notes.  The Company shall have duly executed and delivered to
                   -----                                                        
the Agent a Revolving Note for each Lender having a Commitment with respect
thereto.

          5.1.2.   Payment of Fees.  The Company shall have paid to the Agent 
                   ---------------
and to the Syndication Agent the fees contemplated by separate agreements
between the Company and each of the Agent and the Syndication Agent, dated on or
prior to the date hereof.

          5.1.3.   Legal Opinions.  On the Effective Date, the Lenders shall 
                   --------------
have received from the following counsel their respective opinions with respect
to the transactions contemplated by the Credit Documents, which opinions shall
be in form and substance reasonably satisfactory to the Required Lenders:

          (1)   Gunster, Yoakley, Valdes-Fauli & Stewart, P.A., special counsel
     for the Company and its Subsidiaries.

          (2)   Ropes & Gray, special counsel for the Agent.

          The Company authorizes and directs its special counsel to furnish the
     foregoing opinions.

          5.1.4.   Guarantee and Security Agreement; Parent Pledge and
                   ---------------------------------------------------
     Subordination Agreement, etc.  Each of the Company and the Guarantors shall
     ----------------------------               
     have duly authorized, executed and delivered to the Agent an Amended and
     Restated Guarantee and Security Agreement in substantially the form of
     Exhibit 5.1.4A (the "Guarantee and Security Agreement"), as well as patent
                          --------------------------------
     and trademark security agreements and copyright security agreements
     (collectively, "Intellectual Property Security Agreements") contemplated
                     -----------------------------------------
     therein. The Parent, the Company and its Subsidiaries shall have duly
     authorized, executed and delivered to the Agent a Parent Pledge and
     Subordination Agreement in substantially the form of Exhibit 5.1.4B (the
     "Parent Pledge and Subordination Agreement") and the Parent shall have duly
      -----------------------------------------
     authorized, executed and delivered to the Agent Intellectual Property
     Security Agreements with respect to the patents and trademarks owned by it.
     Each of the Parent and the Company shall have duly authorized, executed and
     delivered to the Agent the Borrower Assumption Agreement.

          5.1.5.   Perfection of Security.  Each Obligor shall have duly
                   ----------------------                               
     authorized, executed, acknowledged, delivered, filed, registered and
     recorded such security

                                      -49-

 
     agreements, notices, financing statements and other instruments as the
     Agent may have reasonably requested in order to perfect the Liens purported
     or required pursuant to the Credit Documents to be created in the Credit
     Security and shall have paid all filing or recording fees or taxes required
     to be paid in connection therewith, including any recording, mortgage,
     documentary, transfer or intangible taxes.

          5.1.6.   Solvency.  After giving effect to the incurrence of the 
                   --------
     Credit Obligations, the Company and its Subsidiaries, taken as a whole:

          (1)   will be solvent;

          (2)   will have assets having a fair saleable value in excess of the
     amount required to pay their probable liability on their existing debts as
     such debts become absolute and mature;

          (3)   will have access to adequate capital for the conduct of their
     business; and

          (4)   will have the ability to pay their debts from time to time
     incurred as such debts mature.

          The Company shall have furnished to the Lenders a certificate of a
     Financial Officer to such effect.

          5.1.7.   No Material Adverse Change in Syndication Market.  Since
                   ------------------------------------------------        
     February 15, 1998, no material adverse change shall have occurred (a) in
     the syndication market for credit facilities similar in nature to the
     credit facility provided hereunder or (b) in the financial, banking or
     capital markets that would have a materially adverse effect on such
     syndication market.

          5.1.8.   Proper Proceedings.  This Agreement, each other Credit 
                   ------------------
     Document and the transactions contemplated hereby and thereby shall have
     been authorized by all necessary corporate or other proceedings. All
     necessary consents, approvals and authorizations of any governmental or
     administrative agency or any other Person of any of the transactions
     contemplated hereby or by any other Credit Document shall have been
     obtained and shall be in full force and effect.

          5.1.9.   General.  All legal and corporate proceedings in connection
                   -------
     with the transactions contemplated by this Agreement shall be reasonably
     satisfactory in form and substance to the Agent and the Agent shall have
     received copies of all documents, including certified copies of the Charter
     and By-Laws of the Company and the other Obligors, records of corporate
     proceedings, certificates as to signatures and incumbency of officers and
     opinions of counsel, which the Agent may have reasonably 

                                      -50-

 
     requested in connection therewith, such documents where appropriate to be
     certified by proper corporate or governmental authorities.

     5.2. Conditions to Each Extension of Credit.  The obligations of the
          --------------------------------------                         
Lenders to make any extension of credit pursuant to Section 2 shall be subject
to the satisfaction, on or before the Closing Date for such extension of credit,
of the following conditions:

          5.2.1.   Officer's Certificate.  The representations and warranties
                   ---------------------                                     
     contained in Section 7 shall be true and correct on and as of such Closing
     Date with the same force and effect as though made on and as of such date
     (except as to any representation or warranty which refers to a specific
     earlier date); no Default shall exist on such Closing Date prior to or
     immediately after giving effect to the requested extension of credit;
     except as otherwise disclosed in writing to the Lenders prior to the date
     hereof, no Material Adverse Change shall have occurred since December 31,
     1997; and the Company shall have furnished to the Agent in connection with
     the requested extension of credit a certificate to these effects, in
     substantially the form of Exhibit 5.2.1, signed by a Financial Officer.

          5.2.2.   Legality, etc.  The making of the requested extension of 
                   -------------
     credit shall not (a) subject any Lender to any penalty or special tax
     (other than a Tax for which the Company is required to reimburse the
     Lenders under Section 3.5), (b) be prohibited by any Legal Requirement or
     (c) violate any credit restraint program of the executive branch of the
     government of the United States of America, the Board of Governors of the
     Federal Reserve System or any other governmental or administrative agency
     so long as any Lender reasonably believes that compliance therewith is
     customary commercial practice.

6.   GENERAL COVENANTS.  Each of the Company, the Guarantors and (only with
     -----------------                                                     
respect to Sections 6.2.1, 6.4, 6.6, 6.7, 6.8, 6.9, 6.11, 6.21 and 6.22) the
Parent covenants that, until all of the Credit Obligations shall have been paid
in full and until the Lenders' commitments to extend credit under this Agreement
and any other Credit Document shall have been irrevocably terminated, each of
the Company, the Parent and their respective Subsidiaries will comply with the
following provisions that are expressly applicable to it:

                                      -51-

 
     6.1.  Taxes and Other Charges; Accounts Payable.
           ----------------------------------------- 

           6.1.1.   Taxes and Other Charges.  Each of the Company and its
                    -----------------------                              
     Subsidiaries shall duly pay and discharge, or cause to be paid and
     discharged, before the same becomes in arrears, all taxes, assessments and
     other governmental charges imposed upon such Person and its properties,
     sales or activities, or upon the income or profits therefrom, as well as
     all claims for labor, materials or supplies which if unpaid might by law
     become a Lien upon any of its property; provided, however, that any such
                                             --------  -------
     tax, assessment, charge or claim need not be paid if the validity or amount
     thereof shall at the time be contested in good faith by appropriate
     proceedings and if such Person shall, in accordance with GAAP, have set
     aside on its books adequate reserves with respect thereto; and provided,
                                                                    --------  
     further, that each of the Company and its Subsidiaries shall pay or bond, 
     -------                                               
     or cause to be paid or bonded, all such taxes, assessments, charges or
     other governmental claims immediately upon the commencement of proceedings
     to foreclose any Lien which may have attached as security therefor (except
     to the extent such proceedings have been dismissed or stayed).

          6.1.2.   Accounts Payable.  Each of the Company and its Subsidiaries
                   ----------------                                           
     shall promptly pay when due, or in conformity with customary trade terms,
     all accounts payable incident to the operations of such Person not referred
     to in Section 6.1.1; provided, however, that any such accounts payable need
                          --------  -------
     not be paid if the validity or amount thereof shall at the time be
     contested in good faith and if such Person shall, in accordance with GAAP,
     have set aside on its books adequate reserves with respect thereto.

     6.2. Conduct of Business, etc.
          ------------------------ 

          6.2.1.   Types of Business.  The Company, its Subsidiaries and the 
                   -----------------
     Parent shall engage only in the business of (a) constructing, owning,
     operating, leasing, managing and acquiring Towers and Tower Companies,
     leasing space on such Towers to tenants, managing the construction of,
     ownership of and leasing of space on Towers for third parties, and
     providing site administration and development services to wireless
     telecommunications carriers and (b) other activities related thereto.

                                      -52-

 
          6.2.2.   Maintenance of Properties.  Each of the Company and its
                   -------------------------                              
     Subsidiaries:

          (1)   shall keep its properties in such repair, working order and
     condition, and shall from time to time make such repairs, replacements,
     additions and improvements thereto, as are necessary for the efficient
     operation of its businesses and shall comply at all times in all material
     respects with all material franchises, licenses and leases to which it is
     party so as to prevent any loss or forfeiture thereof or thereunder, except
     where (i) compliance is at the time being contested in good faith by
     appropriate proceedings and (ii) failure to comply with the provisions
     being contested has not resulted, and does not create a reasonable risk of
     resulting, in the aggregate in any Material Adverse Change; and

          (2)   shall do all things necessary to preserve, renew and keep in
     full force and effect and in good standing its legal existence and
     authority necessary to continue its business; provided, however, that this
                                                   --------  -------           
     Section 6.2.2(b) shall not prevent the merger, consolidation or liquidation
     of Subsidiaries permitted by Section 6.11.

          6.2.3.   Statutory Compliance.  Each of the Company and its 
                   --------------------
     Subsidiaries shall comply in all material respects with all valid and
     applicable statutes, laws, ordinances, zoning and building codes and other
     rules and regulations of the United States of America, of the states and
     territories thereof and their counties, municipalities and other
     subdivisions and of any foreign country or other jurisdictions applicable
     to such Person, except where (a) compliance therewith shall at the time be
     contested in good faith by appropriate proceedings and (b) failure so to
     comply with the provisions being contested has not resulted, and does not
     create a reasonable risk of resulting, in the aggregate in any Material
     Adverse Change.

          6.2.4.   Compliance with Material Agreements.  Each of the Company and
                   -----------------------------------                          
     its Subsidiaries shall comply in all material respects with the Material
     Agreements (to the extent not in violation of the other provisions of this
     Agreement or any other Credit Document). Without the prior written consent
     of the Required Lenders, no Material Agreement shall be amended, modified,
     waived or terminated in any manner that would have in any material respect
     an adverse effect on the interests of the Lenders under the Credit
     Documents.

     6.3. Insurance.
          --------- 

          6.3.1.   Property Insurance.  Each of the Company and its Subsidiaries
                   ------------------                                           
     shall keep its assets which are of an insurable character insured by
     financially sound and reputable insurers against theft and fraud and
     against loss or damage by fire, explosion and hazards insured against by
     extended coverage to the extent, in amounts 

                                      -53-

 
     and with deductibles at least as favorable as those generally maintained by
     businesses of similar size engaged in similar activities.

          6.3.2.   Liability Insurance.  Each of the Company and its 
                   -------------------
     Subsidiaries shall maintain with financially sound and reputable insurers
     insurance against liability for hazards, risks and liability to persons and
     property to the extent, in amounts and with deductibles at least as
     favorable as those generally maintained by businesses of similar size
     engaged in similar activities; provided, however, that it may effect 
                                    --------  -------
     workers' compensation insurance or similar coverage with respect to
     operations in any particular state or other jurisdiction through an
     insurance fund operated by such state or jurisdiction or by meeting the
     self-insurance requirements of such state or jurisdiction.

          6.3.3.   Key Executive Life Insurance.  The Company shall maintain 
                   ----------------------------
     with financially sound and reputable insurers life insurance policies on
     Steven E. Bernstein in an amount of at least $3,000,000 in form reasonably
     satisfactory to the Agent.

          6.3.4.   Flood Insurance.  To the extent necessary to ensure that the
                   ---------------                                             
     Lenders are in compliance with all applicable banking regulations, each of
     the Company and its Subsidiaries shall at all times keep each parcel of
     real property owned or leased by it which is (a) encumbered by a lien in
     favor of the Lenders, (b) in an area determined by the Director of the
     Federal Emergency Management Agency to be subject to special flood hazard
     and (c) in a community participating in the National Flood Insurance
     Program, insured against such special flood hazards in an amount equal to
     the lesser of the value of the insurable improvements located upon such
     real property or the maximum limit of coverage available for the particular
     type of property under the federal National Flood Insurance Act of 1968.

     6.4. Financial Statements and Reports.  Each of the Company and its
          --------------------------------                              
Subsidiaries and the Parent shall maintain a system of accounting in which
correct entries shall be made of all transactions in relation to their business
and affairs in accordance with generally accepted accounting practice.  The
fiscal year of the Company and its Subsidiaries and the Parent shall end on
December 31 in each year and the fiscal quarters of the Company and its
Subsidiaries and the Parent shall end on March 31, June 30, September 30 and
December 31 in each year.

          6.4.1.   Annual Reports.  The Company shall furnish to the Lenders as
                   --------------                                              
     soon as available, and in any event within 120 days after the end of each
     fiscal year, the Consolidated and Consolidating balance sheets of the
     Company and its Subsidiaries and the Parent and its Subsidiaries as at the
     end of such fiscal year, the Consolidated and Consolidating statements of
     income and Consolidated statements of changes in shareholders' equity and
     of cash flows of the Company and its Subsidiaries and the Parent and its
     Subsidiaries for such fiscal year (all in reasonable detail) and together,
     in 

                                      -54-

 
     the case of Consolidated financial statements, with comparative figures for
     the immediately preceding fiscal year, all accompanied by:

          (1)   Reports of Arthur Andersen LLP (or, if they cease to be auditors
     of the Company and its Subsidiaries and the Parent and its Subsidiaries,
     other independent certified public accountants of recognized national
     standing reasonably satisfactory to the Required Lenders), containing no
     material qualification, to the effect that they have audited the foregoing
     Consolidated financial statements in accordance with GAAP and that such
     Consolidated financial statements present fairly, in all material respects,
     the financial position of the Company and its Subsidiaries and the Parent
     and its Subsidiaries covered thereby at the dates thereof and the results
     of their operations for the periods covered thereby in conformity with
     GAAP.

          (2)   The statement of such accountants that they have caused this
     Agreement to be reviewed and that in the course of their audit of the
     Company and its Subsidiaries no facts have come to their attention that
     cause them to believe that any Default exists under Section 6.5 or, if such
     is not the case, specifying such Default and the nature thereof. This
     statement is furnished by such accountants with the understanding that the
     examination of such accountants cannot be relied upon to give such
     accountants knowledge of any such Default except as it relates to
     accounting or auditing matters within the scope of their audit.

          (3)   A certificate of the Company signed by a Financial Officer to
     the effect that such officer has caused this Agreement to be reviewed and
     has no knowledge of any Default, or if such officer has such knowledge,
     specifying such Default and the nature thereof, and what action the Company
     has taken, is taking or proposes to take with respect thereto.

          (4)   Computations by the Company comparing the financial statements
     referred to above with the most recent budget for such fiscal year
     furnished to the Lenders in accordance with Section 6.4.5.

          (5)   Computations by the Company in substantially the form of Exhibit
     6.4 demonstrating, as of the end of such fiscal year, compliance with the
     Computation Covenants, certified by a Financial Officer.

          (6)   Calculations, as at the end of such fiscal year, of (i) the
     Accumulated Benefit Obligations for each Plan (other than Multiemployer
     Plans) and (ii) the fair market value of the assets of such Plan allocable
     to such benefits.

          (7)   A schedule, certified by a Financial Officer, showing as of the
     end of such fiscal year (i) the location of all Towers, whether such Tower
     or the real property 

                                      -55-

 
     on which it is located is owned or leased by the Company and its
     Subsidiaries, the contribution by each Tower to Consolidated Site Leasing
     Revenues as then estimated in good faith by the Company, which Towers were
     acquired during the most recently completed fiscal quarter and the status
     of all Towers under construction and (ii) an open bid summary report and a
     site development backlog report with respect to Towers.

          (8)   Supplements to Exhibits 7.1 and 7.3 showing any changes in the
     information set forth in such exhibits not previously furnished to the
     Lenders in writing, as well as any changes in the Charter, By-laws or
     incumbency of officers of the Obligors from those previously certified to
     the Agent.

          (9)   In the event of a change in GAAP after December 31, 1997,
     computations by the Company, certified by a Financial Officer, reconciling
     the financial statements referred to above with financial statements
     prepared in accordance with GAAP as applied to the other covenants in
     Section 6 and related definitions.

          6.4.2.   Quarterly Reports.  The Company shall furnish to the Agent as
                   -----------------                                            
     soon as available and, in any event, within 45 days after the end of each
     of the first three fiscal quarters of the Company, the internally prepared
     Consolidated balance sheets of the Company and its Subsidiaries and the
     Parent and its Subsidiaries as of the end of such fiscal quarter, the
     Consolidated statements of income and Consolidated statements of changes in
     shareholders' equity and of cash flows of the Company and its Subsidiaries
     and the Parent and its Subsidiaries for such fiscal quarter and for the
     portion of the fiscal year then ended (all in reasonable detail) and
     together, in the case of Consolidated statements, with comparative figures
     for the same period in the preceding fiscal year, all accompanied by:

          (1)   A certificate of the Company signed by a Financial Officer to
     the effect that such Consolidated financial statements have been prepared
     in accordance with GAAP and present fairly, in all material respects, the
     financial position of the Company and its Subsidiaries and the Parent and
     its Subsidiaries covered thereby at the dates thereof and the results of
     their operations for the periods covered thereby, subject only to normal
     year-end audit adjustments and the addition of footnotes.

          (2)   A certificate of the Company signed by a Financial Officer to
     the effect that such officer has caused this Agreement to be reviewed and
     has no knowledge of any Default, or if such officer has such knowledge,
     specifying such Default and the nature thereof and what action the Company
     has taken, is taking or proposes to take with respect thereto.

                                      -56-

 
          (3)   Computations by the Company comparing the financial statements
     referred to above with the most recent budget for the period covered
     thereby furnished to the Lenders in accordance with Section 6.4.5.

          (4)   Computations by the Company in substantially the form of Exhibit
     6.4 demonstrating, as of the end of such quarter, compliance with the
     Computation Covenants, certified by a Financial Officer.

          (5)  A schedule, certified by a Financial Officer, showing as of the
     end of such fiscal quarter (i) the location of all Towers, whether such
     Tower or the real property on which it is located is owned or leased by the
     Company and its Subsidiaries, the contribution by each Tower to
     Consolidated Site Leasing Revenues as then estimated in good faith by the
     Company, which Towers were acquired during such fiscal quarter and the
     status of all Towers under construction and (ii) an open bid summary report
     and a site development backlog report with respect to Towers.

          (6)   Supplements to Exhibits 7.1 and 7.3 showing any changes in the
     information set forth in such exhibits not previously furnished to the
     Lenders in writing, as well as any changes in the Charter, By-laws or
     incumbency of officers of the Obligors from those previously certified to
     the Agent.

          6.4.3.   Monthly Reports.  The Company shall furnish to the Agent as
                   ---------------
     soon as available and, in any event, (a) within 30 days after the end of
     each month, the monthly management report of the Company and its
     Subsidiaries in the form prepared by the Company's management for its own
     internal purposes, which report shall include at least an income statement
     and balance sheet for such month and (b) prior to the end of each month the
     Company's plans for the construction of "build-to-suit" Towers for the next
     month.

          6.4.4.   Tower Acquisition Reports.  The Company will deliver to the
                   -------------------------                                  
     Agent seven Banking Days' (two Banking Days' if the proposed cost is less
     than $2,500,000 for any acquisition or series of related acquisitions)
     prior written notice of the proposed acquisition of any new Towers
     (including real property sites for Towers) if the proposed cost exceeds
     $1,000,000 for any acquisition or series of related acquisitions and the
     proposed cost and projected revenue thereof (whether or not the costs of
     such acquisition are to be funded by the Company from its own sources or
     from the proceeds of the Loan). Such notice shall specify a description and
     the locations of the new Towers (including Towers owned by Tower
     Companies), the name and address of the owner or lessee, as appropriate, of
     the real property on which they are located and, if the proposed cost
     exceeds $2,500,000 for any acquisition or series of related acquisitions, a
     memorandum summarizing the results of the due diligence review of such
     acquisition or series of related acquisitions and such other documents or
     

                                      -57-

 
     information owned or within the control of the Company and its Subsidiaries
     as the Required Lenders may reasonably require.

          6.4.5.   Other Reports.  The Company shall promptly furnish to the
                   -------------                                            
     Lenders:

          (1)   As soon as prepared and in any event within 30 days after the
     beginning of each fiscal year, an annual budget and operating projections
     for such fiscal year of the Company and its Subsidiaries, prepared in a
     manner consistent with the manner in which the financial projections
     described in Section 7.2.1 were prepared.

          (2)   Any material updates of such budget and projections.

          (3)   Any management letters furnished to the Company or any of its
     Subsidiaries or the Parent or any of its Subsidiaries by the Company's
     auditors.

          (4)   All budgets, projections, statements of operations and other
     reports furnished generally to the shareholders of the Parent.

          (5)   Such registration statements, proxy statements and reports,
     including Forms S-1, S-2, S-3, S-4, 10-K, 10-Q and 8-K, as may be filed by
     the Company or any of its Subsidiaries or the Parent or any of its
     Subsidiaries with the Securities and Exchange Commission.

          (6)   Any 90-day letter or 30-day letter from the federal Internal
     Revenue Service (or the equivalent notice received from state or other
     taxing authorities) asserting tax deficiencies against the Company or any
     of its Subsidiaries or the Parent or any of its Subsidiaries.

          6.4.6.   Notice of Litigation, Defaults, etc.  The Company shall 
                   -----------------------------------
     promptly furnish to the Lenders notice of any litigation or any
     administrative or arbitration proceeding (a) which creates a reasonable
     risk of resulting, after giving effect to any applicable insurance, in the
     payment by the Parent and its Subsidiaries of more than $500,000 or (b)
     which results, or creates a reasonable risk of resulting, in a Material
     Adverse Change. Promptly upon acquiring knowledge thereof, the Company
     shall notify the Lenders of the existence of any Default or Material
     Adverse Change, specifying the nature thereof and what action the Parent or
     any of its Subsidiaries has taken, is taking or proposes to take with
     respect thereto.

          6.4.7.   ERISA Reports.  The Company shall furnish to the Lenders as
                   -------------
      soon as available the following items with respect to any Plan:

                                      -58-

 
          (1)   any request for a waiver of the funding standards or an
     extension of the amortization period,

          (2)   any reportable event (as defined in section 4043 of ERISA),
     unless the notice requirement with respect thereto has been waived by
     regulation,

          (3)   any notice received by any ERISA Group Person that the PBGC has
     instituted or intends to institute proceedings to terminate any Plan, or
     that any Multiemployer Plan is insolvent or in reorganization,

          (4)   notice of the possibility of the termination of any Plan by its
     administrator pursuant to section 4041 of ERISA, and

          (5)   notice of the intention of any ERISA Group Person to withdraw,
     in whole or in part, from any Multiemployer Plan.

          6.4.8.   Other Information.  From time to time at reasonable intervals
                   -----------------                                            
     (but in no event more often than quarterly, unless an Event of Default has
     occurred and is continuing) upon written request of any authorized officer
     of any Lender, each of the Company and its Subsidiaries shall furnish to
     the Lenders such other information regarding the business, assets,
     financial condition, income or prospects of the Company and its
     Subsidiaries as such officer may reasonably request, including copies of
     all tax returns, licenses, agreements, leases and instruments to which any
     of the Company or its Subsidiaries is party. The Lenders' authorized
     officers and representatives shall have the right during normal business
     hours upon reasonable notice and at reasonable intervals (but in no event
     more often than quarterly, unless an Event of Default has occurred and is
     continuing) to examine the books and records of the Company and its
     Subsidiaries, to make copies and notes therefrom for the purpose of
     ascertaining compliance with or obtaining enforcement of this Agreement or
     any other Credit Document. The Lenders shall take reasonable steps to
     coordinate any such visits to the Company and its Subsidiaries so as to
     minimize disruption to the Company's operations.

     6.5.    Certain Financial Tests.
             ----------------------- 

             6.5.1.  Consolidated Total Debt to Consolidated Adjusted EBITDA.
                     ------------------------------------------------------- 
     Consolidated Total Debt shall not on any date set forth in the table below
     exceed the percentage set forth in the table below of Consolidated Adjusted
     EBITDA for the most recently completed period of four consecutive fiscal
     quarters for which financial reports have been (or are required to have
     been) furnished to the Lenders in accordance with Section 6.4.1 or 6.4.2.

                                      -59-

 
                      Period                               Percentage
                      ------                               ----------
                                                                    
          Prior to Tower Threshold Date                       500%   
                                                                   
          Tower Threshold Date through March 31, 2000         600%  

          April 1, 2000 through March 31, 2001                500%
                                                                 
          April 1, 2001 through March 31, 2002                400%
                                                                 
          April 1, 2002 and thereafter                        300%


          6.5.2.   Consolidated Adjusted EBITDA to Consolidated Pro Forma 
                   ------------------------------------------------------
     Interest Expense.  As of the last day of each fiscal quarter of the 
     ----------------
     Company, Consolidated Adjusted EBITDA for the period of four consecutive
     fiscal quarters then ending shall exceed 250% of Consolidated Pro Forma
     Interest Expense for the period of four consecutive fiscal quarters
     commencing immediately after such date.

          6.5.3.   Consolidated EBITDA to Consolidated Fixed Charges.  For each
                   -------------------------------------------------           
     period of four consecutive fiscal quarters of the Company, commencing with
     the period ending on June 30, 1999, Consolidated EBITDA shall exceed 120%
     of Consolidated Fixed Charges.

          6.5.4.   Consolidated Adjusted EBITDA.  For each period of four
                   ----------------------------                          
     consecutive fiscal quarters of the Company, commencing with the period
     ending on the earlier of (a) the last day of the fiscal quarter during
     which the Revolving Loan is first outstanding in accordance with Section
     2.1.1 and (b) June 30, 1999, Consolidated Adjusted EBITDA shall equal or
     exceed the amount specified in such table.

          Period Ending                                             Amount
          -------------                                             ------   
 
          September 30, 1998                                        $ 2,500,000
                                                                              
          October 1, 1998 through December 31, 1998                 $ 2,500,000
                                                                              
          January 1, 1999 through March 31, 1999                    $ 4,250,000
                                                                              
          April 1, 1999 through June 30, 1999                       $ 8,000,000
                                                                              
          July 1, 1999 through September 30, 1999                   $ 9,500,000
                                                                              

                                      -60-

 
          October 1, 1999  through December 31, 1999                $11,500,000
                                                                              
          January 1, 2000 through March 31, 2000                    $16,000,000
                                                                              
          April 1, 2000 through June 30, 2000                       $20,000,000
                                                                              
          July 1, 2000 through September 30, 2000                   $25,000,000
                                                                              
          October 1, 2000 through December 31, 2000                 $28,500,000
                                                                              
          January 1, 2001 through March 31, 2002                    $30,000,000
                                                                              
          April 1, 2002 through March 31, 2003                      $35,000,000
                                                                              
          April 1, 2003 and thereafter                              $40,000,000

          6.5.5.   Consolidated Adjusted EBITDA to Consolidated Pro Forma Fixed
                   ------------------------------------------------------------
     Charges.  On the last day of each fiscal quarter of the Company, 
     -------
     commencing with the fiscal quarter ending in March 2002, Consolidated
     Adjusted EBITDA for the period of four consecutive fiscal quarters then
     ending shall exceed 110% of Consolidated Pro Forma Fixed Charges for the 
     12-month period beginning immediately after such date.

          6.5.6.   Overdue Tower Construction Receivables.  Accounts receivable
                   --------------------------------------                      
     that are more than 60 days overdue owing to the Company and its
     Subsidiaries with respect to any third-party construction (including
     construction of Towers, site work and installation of antenna and other
     operating equipment) shall not exceed $1,500,000 in the aggregate at any
     one time outstanding.

          6.5.7.   Capital Expenditures.  Capital Expenditures by the Company 
                   --------------------
     and its Subsidiaries with respect to Towers to be constructed and owned by
     the Company and its Subsidiaries shall not exceed (a) $125,000,000 in the
     aggregate for the fiscal year ending December 31, 1998, (b) $140,000,000 in
     the aggregate for the fiscal year ending December 31, 1999, and (c)
     $5,000,000 in the aggregate in any fiscal year thereafter.

          6.5.8.   Executive Management Compensation.  Salaries, cash bonuses,
                   ---------------------------------                          
     management and consulting fees and other compensation expenses payable by
     the Company and its Subsidiaries to Executive Management shall not exceed
     (a) $2,750,000 in fiscal year 1998, and (b) in any fiscal year thereafter,
     115% of the maximum amount permitted by this Section 6.5.8 for the then
     previous fiscal year.

                                      -61-

 
     6.6. Indebtedness.  Neither the Company nor any of its Subsidiaries nor the
          ------------                                                          
Parent nor any of its Subsidiaries shall create, incur, assume or otherwise
become or remain liable with respect to any Indebtedness (or become
contractually committed to do so), except the following:

          6.6.1.  Indebtedness in respect of the Credit Obligations.

          6.6.2.  Guarantees permitted by Section 6.7.

          6.6.3.  Current liabilities, other than Financing Debt, incurred in
     the ordinary course of business.

          6.6.4.  To the extent that payment thereof shall not at the time be
     required by Section 6.1, Indebtedness in respect of taxes, assessments,
     governmental charges and claims for labor, materials and supplies.

          6.6.5.  Indebtedness secured by Liens of carriers, warehouses,
     mechanics and landlords permitted by Sections 6.8.5 and 6.8.6.

          6.6.6.  Indebtedness in respect of judgments or awards (a) which have
     been in force for less than the applicable appeal period or (b) in respect
     of which the Company or any Subsidiary shall at the time in good faith be
     prosecuting an appeal or proceedings for review and, in the case of each of
     clauses (a) and (b), the Company or such Subsidiary shall have taken
     appropriate reserves therefor in accordance with GAAP or such liability
     shall be covered by insurance and execution of such judgment or award shall
     not be levied.

          6.6.7.  To the extent permitted by Section 6.8.7, Indebtedness in
     respect of Capitalized Lease Obligations or secured by purchase money
     security interests; provided, however, that the aggregate principal amount
                         --------  -------                                     
     of all Indebtedness under this Section 6.6.7 plus Indebtedness under
                                                  ----                   
     Sections 6.6.8(a), 6.6.14 and 6.6.15 at any one time outstanding shall not
     exceed $5,000,000.

          6.6.8.  Unsecured Indebtedness owing to sellers of Towers and Tower
     Companies so long as either (a) such Indebtedness is subordinated to the
     Credit Obligations on substantially the terms of Exhibit 6.6.8 and the
     aggregate principal amount of all Indebtedness under this clause (a) plus
                                                                          ----
     Indebtedness under Sections 6.6.7, 6.6.14 and 6.6.15 at any one time
     outstanding shall not exceed $5,000,000 or (b) the aggregate principal
     amount of Indebtedness owing to such sellers is covered by Letters of
     Credit.

                                      -62-

 
          6.6.9.    Indebtedness in respect of deferred taxes arising in the
     ordinary course of business and deferred insurance expense financed for a
     period not to exceed 12 months.

          6.6.10.   Indebtedness in respect of inter-company loans and advances
     among the Company and its Subsidiaries which are not prohibited by Section
     6.9.

          6.6.11.   Unsecured Indebtedness of the Company or the Parent
     subordinated to the prior payment of the Credit Obligations upon customary
     terms reasonably satisfactory to the Lenders, including a final maturity
     date of at least one year after the Final Maturity Date, covenants less
     restrictive on the Company and its Subsidiaries other than the covenants
     contained in this Agreement and customary subordination provisions;
     provided, however, that the proceeds of such Indebtedness are used to fund
     --------  -------   
     the acquisition or construction of Towers; and provided further, that the
                                                    --------    
     aggregate principal amount of all Indebtedness permitted by this Section
     6.6.11 at any one time outstanding shall not exceed $100,000,000.

          6.6.12.   Unfunded pension liabilities and obligations with respect to
     Plans so long as the Company and all other ERISA Group Persons are in
     compliance with Section 6.16.

          6.6.13.   Indebtedness (in addition to the foregoing) outstanding on
     the date hereof and described in Exhibit 7.3 and all renewals and
     extensions thereof not in excess of the amount thereof outstanding
     immediately prior to such renewal or extension.

          6.6.14.   Indebtedness of Foreign Subsidiaries in an aggregate
     principal amount not exceeding $1,000,000 at any one time outstanding in an
     equivalent amount of United States Funds; provided, however, that the
                                               --------  -------          
     aggregate principal amount of all Indebtedness under this Section 6.6.14
     plus Indebtedness under Sections 6.6.7, 6.6.8(a) and 6.6.15 at any one time
     ----                                                                       
     outstanding shall not exceed $5,000,000.

          6.6.15.   Indebtedness (other than Financing Debt) in addition to the
     other Indebtedness permitted by this Section 6.6; provided, however, that
                                                       --------  -------      
     the aggregate amount of all Indebtedness under this Section 6.6.15 plus
                                                                        ----
     Indebtedness under Sections 6.6.7, 6.6.8(a) and 6.6.14 at any one time
     outstanding shall not exceed $5,000,000.

          6.6.16.   Indebtedness incurred by the Parent with respect to the
     Parent Discount Notes.

     6.7  Guarantees; Letters of Credit.  Neither the Company nor any of its
          -----------------------------                                     
Subsidiaries nor the Parent nor any of its Subsidiaries shall become or remain
liable with respect to any 

                                      -63-

 
Guarantee, including reimbursement obligations, whether contingent or matured,
under letters of credit or other financial guarantees by third parties (or
become contractually committed do to so), except the following:

          6.7.1.   Letters of Credit and Guarantees of the Credit Obligations.

          6.7.2.   Guarantees by the Company of Indebtedness and other
     obligations incurred by its Subsidiaries and permitted by Section 6.6.

     6.8. Liens.   Neither the Company nor any of its Subsidiaries nor the 
          -----                                                                 
Parent nor any of its Subsidiaries shall create, incur or enter into, or suffer
to be created or incurred or to exist, any Lien (or become contractually
committed to do so), except the following:

          6.8.1.   Liens on the Credit Security that secure the Credit
     Obligations.

          6.8.2.   Liens to secure taxes, assessments and other governmental
     charges, to the extent that payment thereof shall not at the time be
     required by Section 6.1.

          6.8.3.   Deposits or pledges made (a) in connection with, or to secure
     payment of, workers' compensation, unemployment insurance, old age pensions
     or other social security, (b) in connection with casualty insurance
     maintained in accordance with Section 6.3, (c) to secure the performance of
     bids, tenders, contracts (other than contracts relating to Financing Debt)
     or leases, (d) to secure statutory obligations or surety or appeal bonds,
     (e) to secure indemnity, performance or other similar bonds or guarantees
     in the ordinary course of business or (f) in connection with contested
     amounts to the extent that payment thereof shall not at that time be
     required by Section 6.1.

          6.8.4.   Liens in respect of judgments or awards, to the extent that
     such judgments or awards are permitted by Section 6.6.6 but only to the
     extent that such Liens are junior to the Liens on the Credit Security
     granted to secure the Credit Obligations.

          6.8.5.   Liens of carriers, warehouses, mechanics and similar Liens,
     in each case (a) in existence less than 90 days from the date of creation
     thereof or (b) being contested in good faith by the Company or any
     Subsidiary or the Parent in appropriate proceedings (so long as the Company
     or such Subsidiary shall, in accordance with GAAP, have set aside on its
     books adequate reserves with respect thereto).

                                      -64-

 
          6.8.6.   Encumbrances in the nature of (a) zoning restrictions,      
     (b) easements and reservations of mineral rights, (c) restrictions of
     record on the use of real property, (d) landlords' and lessors' Liens on
     rented premises and (e) restrictions on transfers or assignment of leases
     and (f) title irregularities, in all such cases that do not in the
     aggregate materially detract from the value of the Towers taken as a whole
     and that do not result, or create a reasonable risk of resulting, in a
     Material Adverse Change.

          6.8.7.   Liens constituting (a) purchase money security interests
     (including mortgages, conditional sales, Capitalized Leases and any other
     title retention or deferred purchase devices) in real property, interests
     in leases or tangible personal property (other than inventory) existing or
     created on the date on which such property is acquired, and (b) the
     renewal, extension or refunding of any security interest referred to in the
     foregoing clause (a) in an amount not to exceed the amount thereof
     remaining unpaid immediately prior to such renewal, extension or refunding;
     provided, however, that (i) each such security interest shall attach solely
     --------  -------                                                          
     to the particular item of property so acquired, and the principal amount of
     Indebtedness (including Indebtedness in respect of Capitalized Lease
     Obligations) secured thereby shall not exceed the cost (including all such
     Indebtedness secured thereby, whether or not assumed) of such item of
     property; and (ii) the aggregate principal amount of all Indebtedness
     secured by Liens permitted by this Section 6.8.7 shall not exceed the
     amount permitted by Section 6.6.7.

          6.8.8.   Restrictions under federal and state securities laws on the
     transfer of securities.

          6.8.9.   Liens as in effect on the date hereof described in 
     Exhibit 7.3 and securing Indebtedness permitted by Section 6.6.13.

     6.9  Investments and Acquisitions.  Neither the Company nor any of its
          ----------------------------                                     
Subsidiaries nor the Parent nor any of its Subsidiaries shall have outstanding,
acquire or hold any Investment (including any Investment consisting of the
acquisition of any business) (or become contractually committed to do so),
except the following:

          6.9.1.   Investments of the Company and its Subsidiaries or the Parent
     in (a) Wholly Owned Subsidiaries which are Guarantors as of the date hereof
     and (b) Persons that have become Wholly Owned Subsidiaries and Guarantors
     after the date hereof in accordance with Section 6.9.5; provided, however,
                                                             --------  ------- 
     that (i) no such Investment shall involve the transfer by the Company of
     any material assets other than cash and (ii) no such Investments shall be
     made after the date hereof in Foreign Subsidiaries.

                                      -65-

 
          6.9.2.   Intercompany loans and advances from any Wholly Owned
     Subsidiary to the Company but in each case only to the extent reasonably
     necessary for Consolidated tax planning and working capital management;
     provided, however, that loans and advances from a Foreign Subsidiary 
     -------   -------                                                     
     to the Company or a Domestic Subsidiary must be subordinated to the Credit
     Obligations pursuant to a subordination agreement in substantially the same
     form as the Subordination Agreement provided for in Section 5.1.6.

          6.9.3.   Investments in Cash Equivalents.

          6.9.4.   Guarantees permitted by Section 6.7.

          6.9.5.   So long as immediately before and after giving effect thereto
     no Default exists, Investments of the Company and its Wholly Owned
     Subsidiaries and the Parent consisting of the acquisition of Towers and
     all or a portion of the equity of Tower Companies; provided, however, that:
                                                        --------  -------       

          (1)   at least seven Banking Days (two Banking Days in the case of
     acquisitions or series of related acquisitions with a cost to the Company
     and its Subsidiaries and the Parent less than $2,500,000) prior to any such
     acquisition with a cost exceeding $1,000,000, the Lenders shall receive
     computations provided by a Financial Officer demonstrating pro forma
     compliance with the Computation Covenants after giving effect to such
     acquisition and, in the case of any acquisition (or series of related
     acquisitions) involving consideration exceeding $2,500,000 by the Company
     and its Subsidiaries and the Parent, the materials required by Section
     6.4.4,

          (2)   the Company and the Parent shall take all necessary action to
     cause any such newly acquired Tower Company that is a Subsidiary owned at
     least 80% by the Parent and its Subsidiaries to become a Guarantor and to
     perfect the Lenders' security interests in the newly acquired Towers and
     Designated Real Properties to the extent necessary to comply with 
     Section 6.20.3,

          (3)   no more than 25% of the revenues anticipated to be derived from
     such acquired Towers or Tower Companies shall derive from PCS C-Block
     Providers, and

          (4)   in the case of any acquisition (or series of related
     acquisitions) involving consideration exceeding $6,000,000 by the Company
     and its Subsidiaries and the Parent, the Lenders holding at least a
     majority of the Percentage Interests shall have provided their prior
     written consent, and

          (5)   minority investments in the equity of Tower Companies shall in
     no event exceed $15,000,000 in the aggregate at any one time outstanding.

                                      -66-

 
           6.9.6.  $3,500,000 loan from the Parent to Steven E. Bernstein
     evidenced by a note dated March 8, 1997.

     6.10  Distributions.  Neither the Company nor any of its Subsidiaries shall
           -------------                                                        
make any Distribution (or become contractually committed to do so), except the
following:

           6.10.1. So long as immediately before and after giving effect thereto
     no Default exists, Subsidiaries of the Company may make Distributions to
     the Company or any Wholly Owned Subsidiary of the Company and the Company
     and its Subsidiaries may make Investments permitted by Sections 6.9.1 and
     6.9.2.

           6.10.2. So long as immediately before and after giving effect thereto
     no Default exists, and so long as immediately after giving effect thereto
     the Company and its Subsidiaries are in pro forma compliance with the
     Computation Covenants, the Company may make Distributions to the Parent in
     an amount and at the time necessary for the Parent to redeem outstanding
     shares of the Parent's Series A, Series B, Series C and Series D Preferred
     Stock to the extent such redemptions are permitted by section 4.07 of the
     Parent Discount Notes Indenture as in effect on the date hereof without any
     subsequent amendment or modification.

           6.10.3. To the extent permitted by the applicable subordination
     terms, the Company may make (or make Distributions to the Parent to the
     extent necessary for the Parent to make) regularly scheduled, mandatory
     payments of interest on and principal of the subordinated Indebtedness
     permitted by Sections 6.6.8 and 6.6.11.

           6.10.4. So long as immediately before and after giving effect thereto
     no Event of Default exists, the Company may make Distributions to the
     Parent (i) to enable the Parent (a) to pay its general and administrative
     expenses in the ordinary course of business; provided, however, that the
                                                  --------  -------
     aggregate amount of all such Distributions shall in no event exceed
     $2,500,000 in any year and (b) to pay mandatory cash interest on the Parent
     Discount Notes in accordance with their terms; provided, however, that no
                                                    --------  -------    
     such Distributions shall be made prior to the fifth anniversary of the
     consummation of the offering of the Parent Discount Notes.

           6.10.5. So long as immediately before and after giving effect 
     thereto no Event of Default under Section 8.1.1 exists, the Company may
     make Distributions to the Parent in an amount and at the times necessary to
     enable the Parent to pay income taxes due that are properly allocable to
     the operations of the Company and its Subsidiaries under the consolidated
     tax returns of the Parent and its Subsidiaries.

                                      -67-

 
     6.11. Asset Dispositions and Mergers.  Neither the Company nor any of its
           ------------------------------                                     
Subsidiaries nor the Parent nor any of its Subsidiaries shall merge or enter
into a consolidation or sell, lease, exchange, sell and lease back, sublease or
otherwise dispose of any of its assets (or become contractually committed to do
so), except the following:

           6.11.1.  The Company and any of its Subsidiaries may sell or
     otherwise dispose of (a) inventory and Cash Equivalents in the ordinary
     course of business and (b) tangible assets to be replaced in the ordinary
     course of business within 12 months by other tangible assets of equal or
     greater value or (c) tangible assets (other than Towers) that are no longer
     used or useful in the business of the Company or such Subsidiary.

           6.11.2.  Any Wholly Owned Subsidiary of the Company may merge or be
     liquidated into the Company or any other Wholly Owned Subsidiary of the
     Company so long as after giving effect to any such merger to which the
     Company is a party the Company shall be the surviving or resulting Person.

           6.11.3.  Mergers constituting Investments permitted by Section 6.9.5.

           6.11.4.  Licensing of and leasing of Tower space and intangible
     assets for fair value in the ordinary course of business.

           6.11.5.  So long as immediately before and after giving effect
     thereto no Default exists, transfers for fair value to any Person who sells
     or leases a Tower or Tower Company to the Company or one of its
     Subsidiaries of such portions of the real property on which the applicable
     Towers are located as are not necessary for the operation of the Towers.

           6.11.6.  So long as the Net Asset Sale Proceeds thereof are applied
     to repay the Loan as required by Section 4.3.2 and so long as immediately
     before and after giving effect thereto no Default exists, the Company and
     its Subsidiaries may sell for fair value during any year either (a) Towers
     contributing not more than 5% of Consolidated Site Leasing Revenues for the
     Company's most recently completed fiscal year; provided, however, that the
                                                    --------  -------          
     sum of the foregoing percentages of Consolidated Site Leasing Revenues for
     all Towers sold pursuant to this Section 6.11.6(a) since the date hereof
     shall not exceed 15% or (b) Towers in barter or exchange transactions for
     replacement Towers, or the cash proceeds from the sale or other disposition
     of which are used by the Company or any of its Subsidiaries within 180 days
     to acquire or construct Towers.

           6.11.7.  So long as immediately before and after giving effect
     thereto no Default exists, the Company and its Subsidiaries may enter into
     sale and leaseback transactions with respect to the real property upon
     which the Towers are located (but 

                                      -68-

 
     not with respect to the Towers themselves) in an aggregate amount not to
     exceed $200,000.

     6.12. Issuance of Stock by Subsidiaries or the Company; Subsidiary
           ------------------------------------------------------------
Distributions.
- ------------- 

           6.12.1.  Issuance of Stock by Subsidiaries or the Company.  Neither
                    ------------------------------------------------  
     any Subsidiary nor the Company shall issue or sell any shares of its
     capital stock or other evidence of beneficial ownership to any Person other
     than (a) the Company or any Wholly Owned Subsidiary of the Company or the
     Parent, which shares shall have been pledged to the Agent as part of the
     Credit Security to the extent required by the Guarantee and Security
     Agreement or the Parent Pledge and Subordination Agreement, as the case may
     be, and (b) directors of Subsidiaries as qualifying shares to the extent
     required by Legal Requirements and, in the case of Foreign Subsidiaries,
     shares required by Legal Requirements to be held by foreign nationals and
     (c) other equity owners of Subsidiaries acquired and owned in accordance
     with Section 6.9.5.

           6.12.2.  No Restrictions on Subsidiary Distributions.  Except for 
                    -------------------------------------------             
     this Agreement and the Credit Documents, neither the Company nor any
     Subsidiary shall enter into or be bound by any agreement (including
     covenants requiring the maintenance of specified amounts of net worth or
     working capital) restricting the right of any Subsidiary to make
     Distributions or extensions of credit to the Company (directly or
     indirectly through another Subsidiary); provided, however, that
                                             --------  ------- 
     Foreign Subsidiaries may become subject to such restrictions pursuant to
     loan agreements with respect to Indebtedness permitted by Section 6.6.14.

     6.13. Voluntary Prepayments of Other Indebtedness.  Neither the Company 
           -------------------------------------------
nor any of its Subsidiaries shall make any voluntary prepayment of principal of
or interest on any Financing Debt (other than the Credit Obligations) or make
any voluntary redemptions or repurchases of Financing Debt (other than the
Credit Obligations); provided, however, that Company may make the payments
permitted by Section 6.10.3 on subordinated Indebtedness permitted by 
Sections 6.6.8 and 6.6.11.

     6.14. Derivative Contracts.  Neither the Company nor any of its 
           --------------------       
Subsidiaries shall enter into any Interest Rate Protection Agreement, foreign
currency exchange contract or other financial or commodity derivative contracts
except to provide hedge protection for an underlying economic transaction in the
ordinary course of business.

     6.15. Negative Pledge Clauses.  Neither the Company nor any of its
           -----------------------                                     
Subsidiaries shall enter into any agreement, instrument, deed or lease which
prohibits or limits the ability of the Company or any of its Subsidiaries to
create, incur, assume or suffer to exist any Lien upon any of their respective
properties, assets or revenues, whether now owned or hereafter 

                                      -69-

 
acquired, or which requires the grant of any collateral for such obligation if
collateral is granted for another obligation, except the following:

            6.15.1.  This Agreement and the other Credit Documents.

            6.15.2.  Covenants in documents creating Liens permitted by 
     Section 6.8 prohibiting further Liens on the assets encumbered thereby.

     6.16.  ERISA, etc.  Each of the Company and its Subsidiaries shall comply,
            ----------                                                         
and shall cause all ERISA Group Persons to comply, in all material respects,
with the provisions of ERISA and the Code applicable to each Plan.  Each of the
Company and its Subsidiaries shall meet, and shall cause all ERISA Group Persons
to meet, all minimum funding requirements applicable to them with respect to any
Plan pursuant to section 302 of ERISA or section 412 of the Code, without giving
effect to any waivers of such requirements or extensions of the related
amortization periods which may be granted.  At no time shall the Accumulated
Benefit Obligations under any Plan that is not a Multiemployer Plan exceed the
fair market value of the assets of such Plan allocable to such benefits by more
than $1,000,000.  The Company and its Subsidiaries shall not withdraw, and shall
cause all other ERISA Group Persons not to withdraw, in whole or in part, from
any Multiemployer Plan so as to give rise to withdrawal liability exceeding
$1,000,000 in the aggregate.  At no time shall the actuarial present value of
unfunded liabilities for post-employment health care benefits (other than COBRA
continuation coverage benefits), whether or not provided under a Plan,
calculated in a manner consistent with Statement No. 106 of the Financial
Accounting Standards Board, exceed $1,000,000.

     6.17.  Transactions with Affiliates.  Neither the Company nor any of its
            ----------------------------                                     
Subsidiaries shall effect any transaction with any of their respective
Affiliates (except for the Company and its Subsidiaries) on a basis less
favorable to the Company and its Subsidiaries than would be the case if such
transaction had been effected with a non-Affiliate.

     6.18.  Interest Rate Protection. From and after the date the Loan first
            ------------------------                                        
equals or exceeds $37,500,000, the Company shall obtain and thereafter keep in
effect one or more Interest Rate Protection Agreements conforming to
International Securities Dealers Association standards, each in form and
substance reasonably satisfactory to the Agent, covering a notional amount of at
least 50% of the Loan, in each case for an aggregate period of not less than
three years.

                                      -70-

 
     6.19. Environmental Laws.
           ------------------ 

           6.19.1.  Compliance with Law and Permits.  Each of the Company and 
                    ------------------------------- 
     its Subsidiaries shall use and operate all of its facilities and properties
     in material compliance with all Environmental Laws, keep in effect all
     necessary permits, approvals, certificates, licenses and other
     authorizations relating to environmental matters and remain in material
     compliance therewith, and handle all Hazardous Materials in material
     compliance with all applicable Environmental Laws.

           6.19.2.  Notice of Claims, etc.  Each of the Company and its 
                    ---------------------    
     Subsidiaries shall immediately notify the Agent, and provide copies upon
     receipt, of all written claims, complaints, notices or inquiries from
     governmental authorities relating to the condition of its facilities and
     properties or compliance with Environmental Laws, and shall promptly cure
     and have dismissed with prejudice to the reasonable satisfaction of the
     Agent any actions and proceedings relating to compliance with Environmental
     Laws.

     6.20. Tower Matters.
           ------------- 

           6.20.1.  Tower Construction Requirements. Prior to commencement of
                    -------------------------------                          
     construction of any Tower to be owned by the Company or any of its
     Subsidiaries, if at the time Credit Exposure exceeds $1,000,000, the
     Company shall enter into a standard lease agreement with respect to such
     Tower with a licensed cellular operator, PCS A-F Block Provider or ESMR
     Operator as the anchor tenant. The anchor tenant shall be reasonably
     acceptable to the Agent.

           6.20.2.  No Removal of Towers.  None of the Towers located on 
                    --------------------  
     Designated Real Property shall be removed from their locations without the
     prior written consent of the Required Lenders, which consent shall not be
     unreasonably withheld or delayed, unless: (a) (i) such removal is in the
     ordinary course of business, (ii) such actions and filings of record as may
     be necessary to continue the first priority perfected Lien of the Lenders
     in the real property or leasehold upon which such Tower is finally located
     have been taken and (iii) in the case of leaseholds, the Agent has received
     Estoppel and Consent Letters relating to the new locations, or (b) such
     removal is necessary to satisfy any Legal Requirement or a properly issued
     order or mandate of any governmental authority or (c) any Tower so removed
     has been damaged and the Lenders have required the insurance proceeds
     relating thereto be applied to repayment of the Loan in accordance with
     Section 4.3.2.

          6.20.3.   Pledged Towers.  On the date the Revolving Loan is first
                    --------------                                          
     outstanding in accordance with Section 2.1.1 in an amount exceeding $1,000,
     Pledged Towers on such date shall have contributed at least 80% of
     Consolidated Site Leasing 

                                      -71-

 
     Revenues for the period of four consecutive fiscal quarters of the Company
     then most recently ended for which financial reports have been furnished to
     the Lenders in accordance with Section 6.4.1 or 6.4.2. For each period of
     four consecutive fiscal quarters of the Company thereafter, Pledged Towers
     as of the date 45 days after the end of such period shall have contributed
     at least 80% of Consolidated Site Leasing Revenues for such period.

          The Company and its Subsidiaries shall have the right to obtain
     releases and discharges of any Mortgages and Estoppel and Consent Letters
     with respect to Pledged Towers upon 10 Banking Days prior notice to the
     Agent so long as after giving effect to any such releases and discharges
     Pledged Towers shall have contributed at least 80% of Consolidated Site
     Leasing Revenues for the period of four consecutive fiscal quarters of the
     Company then most recently ended.

          With respect to each Pledged Tower, the Obligors shall have duly
     authorized, executed, acknowledged and delivered to the Agent a mortgage
     (or deed of trust) on each real property on which such Pledged Tower is
     located in substantially the form of Exhibit 6.20.3A and a leasehold
     mortgage (or leasehold deed of trust) on each real property leased by the
     Company and its Subsidiaries on which such Pledged Tower is located in
     substantially the form of Exhibit 6.20.3B, with Estoppel and Consent
     Letters from the lessors in substantially the form of Exhibit 6.20.3C
     (each, an "Estoppel and Consent Letter"), lessor waivers and any other
                ---------------------------                                
     documents required to allow for the recording or filing of a leasehold
     mortgage, in each case in form and substance reasonably satisfactory to the
     Agent, together with, for each such real property:  (a) copies of title
     insurance policies to the extent obtained by the Company or any of its
     Subsidiaries, (b) to the extent obtained by the Company or any of its
     Subsidiaries, an environmental site assessment report in such form, with
     such conclusions and from such environmental engineering firm as are
     reasonably satisfactory to the Agent, (c) to the extent obtained by the
     Company or any of its Subsidiaries, a survey on such real property that is
     reasonably satisfactory to the Agent and (d) a legal opinion of local
     counsel with respect to the recording and enforceability of such mortgages
     and leasehold mortgages in substantially the form of Exhibit 6.20.3D.

     6.21.  Series A Preferred Stock Redemptions.  The terms of any redemption
            ------------------------------------      
by the Parent of Series A Preferred Stock shall be consistent with the
restrictions on such redemption as set forth in the Parent Discount Notes
Indenture as in effect on the date hereof without giving effect to any
subsequent amendment or modification.

     6.22.  Restricted Operations of Parent.  The Parent will conduct no
            -------------------------------                             
operations other than acquiring and owning the capital stock of the Company,
advancing funds to the Company and holding evidence of such Indebtedness,
maintaining ownership of trademarks and tradenames 

                                      -72-

 
that are pledged to the Agent in accordance with an Intellectual Property
Security Agreement and activities incidental thereto. The Parent will own no
material assets other than the stock and Indebtedness of the Company, the
trademarks and trade names described above and cash expected to be spent within
90 days in the ordinary course of business.

7.   REPRESENTATIONS AND WARRANTIES.  In order to induce the Lenders to extend
     ------------------------------                                           
credit to the Company hereunder, each of the Company and the Guarantors jointly
and severally represents and warrants as follows:

     7.1   Organization and Business.
           ------------------------- 

           7.1.1.   The Company.  The Company is a duly organized and validly
                    -----------                                              
     existing corporation in good standing under the laws of Florida, with all
     corporate power and authority necessary to (a) enter into and perform this
     Agreement and each other Credit Document to which it is party, (b)
     guarantee the Credit Obligations, (c) grant the Agent for the benefit of
     the Lenders the security interests in the Credit Security owned by it to
     secure the Credit Obligations and (d) own its properties and carry on the
     business now conducted or proposed to be conducted by it. Certified copies
     of the Charter and By-laws of the Company have been previously delivered to
     the Agent and are correct and complete. Exhibit 7.1, as from time to time
     hereafter supplemented in accordance with Sections 6.4.1 and 6.4.2, sets
     forth, as of the later of the date hereof or the end of the most recent
     fiscal quarter for which financial statements are required to be furnished
     in accordance with such Sections, (i) the jurisdiction of incorporation of
     the Company, (ii) the address of the Company's principal executive office
     and chief place of business, (iii) each name, including any trade name,
     under which the Company conducts its business and (iv) the jurisdictions in
     which the Company owns real or tangible personal property.

           7.1.2.   Subsidiaries.  Each Subsidiary of the Company is duly 
                    ------------                                         
     organized, validly existing and in good standing under the laws of the
     jurisdiction in which it is organized, with all corporate power and
     authority necessary to (a) enter into and perform this Agreement and each
     other Credit Document to which it is party, (b)guarantee the Credit
     Obligations, (c) grant the Agent for the benefit of the Lenders the
     security interest in the Credit Security owned by such Subsidiary to secure
     the Credit Obligations and (d) own its properties and carry on the business
     now conducted or proposed to be conducted by it. Certified copies of the
     Charter and By-laws of each Subsidiary of the Company have been previously
     delivered to the Agent and are correct and complete. Exhibit 7.1, as from
     time to time hereafter supplemented in accordance with Sections 6.4.1 and
     6.4.2, sets forth, as of the later of the date hereof or the end of the
     most recent fiscal quarter for which financial statements are required to
     be furnished in accordance with such Sections, (i) the name and
     jurisdiction of organization of each Subsidiary of the Company, (ii) the
     address of the chief executive office and principal

                                      -73-

 
     place of business of each such Subsidiary, (iii) each name under which each
     such Subsidiary conducts its business, (iv) each jurisdiction in which each
     such Subsidiary owns real or tangible personal property, and (v) the number
     of authorized and issued shares and ownership of each such Subsidiary.

           7.1.3.   The Parent.  The Parent is a duly organized and validly 
                    ----------     
     existing corporation in good standing under the laws of Florida, with all
     corporate power and authority necessary to (a) enter into and perform this
     Agreement and each other Credit Document to which it is party, (b) grant
     the Agent for the benefit of the Lenders the security interests in the
     Credit Security owned by it to secure the Credit Obligations and (c) own
     its properties and carry on the business now conducted or proposed to be
     conducted by it. Certified copies of the Charter and By-laws of the Parent
     have been previously delivered to the Agent and are correct and complete.
     Exhibit 7.1, as from time to time hereafter supplemented in accordance with
     Sections 6.4.1 and 6.4.2, sets forth, as of the later of the date hereof or
     the end of the most recent fiscal quarter for which financial statements
     are required to be furnished in accordance with such Sections, (i) the
     jurisdiction of incorporation of the Parent, (ii) the address of the
     Parent's principal executive office and chief place of business, (iii) each
     name, including any trade name, under which the Parent conducts its
     business and (iv) the jurisdictions in which the Parent owns real or
     tangible personal property.

           7.1.4.   Qualification.  Each of the Company, its Subsidiaries and
                    -------------       
     the Parent is duly and legally qualified to do business as a foreign
     corporation or other entity and is in good standing in each state or
     jurisdiction in which such qualification is required and is duly
     authorized, qualified and licensed under all laws, regulations, ordinances
     or orders of public authorities, or otherwise, to carry on its business in
     the places and in the manner in which it is conducted, except for failures
     to be so qualified, authorized or licensed which would not in the aggregate
     result, or create a material risk of resulting, in any Material Adverse
     Change.

           7.1.5.   Capitalization.  No options, warrants, conversion rights,
                    --------------                                           
     preemptive rights or other statutory or contractual rights to purchase
     shares of capital stock or other securities of any Subsidiary now exist,
     nor has any Subsidiary authorized any such right, nor is any Subsidiary
     obligated in any other manner to issue shares of its capital stock or other
     securities.

     7.2.  Financial Statements and Other Information; Material Agreements.
           --------------------------------------------------------------- 

           7.2.1.   Financial Statements and Other Information.  The Company has
                    ------------------------------------------                  
     previously furnished to the Lenders copies of the following:

                                      -74-

 
          (1)   The audited Consolidated balance sheets of the Parent and its
     Subsidiaries as at December 31 in each of 1995, 1996 and 1997 and the
     audited Consolidated statements of income, of changes in shareholders'
     equity and of cash flows of the Parent and its Subsidiaries for the fiscal
     years then ended.

          (2)   The unaudited Consolidated balance sheet of the Parent and its
     Subsidiaries as at March 31, 1998 and the unaudited Consolidated statements
     of income, of changes in shareholders' equity and of cash flows of the
     Parent and its Subsidiaries for the fiscal quarter then ended.

          (3)   The five-year financial and operational projections for the
     Parent and its Subsidiaries dated May 1998.

          (4)   Offering Memorandum dated February 25, 1998 with respect to the
     Parent Discount Notes (the "Offering Memorandum").
                                 -------------------   

          The financial statements (including the notes thereto) referred to in
     clauses (a) and (b) above were prepared in accordance with GAAP and fairly
     present in all material respects the financial position of the Parent and
     its Subsidiaries on a Consolidated basis at the respective dates thereof
     and the results of their operations for the periods covered thereby,
     subject in the case off interim financial statements to the addition of
     footnotes and normal year-end audit adjustments.  Neither the Parent nor
     any of its Subsidiaries has any known contingent liability material to the
     Parent and its Subsidiaries on a Consolidated basis which is not reflected
     in the balance sheets referred to in clauses (a) and (b) above (or
     delivered pursuant to Sections 6.4.1 or 6.4.2) or in the notes thereto.

          In the Parent's judgment, the financial and operational projections
     referred to in clause (c) above constitute a reasonable basis as of the
     Effective Date for the assessment of the future performance of the Parent
     and its Subsidiaries during the periods indicated therein (on a cash
     accounting basis), it being understood that any projected financial
     information represents an estimate, based on various assumptions, of future
     results of operations which may or may not in fact occur.

          As of the date thereof, the Offering Memorandum did not contain any
     untrue statement of a material fact or omit to state a material fact
     necessary in order to make the statements contained therein not misleading
     in light of the circumstances under which they were made; provided,
                                                               -------- 
     however, that the descriptions in the Offering Memorandum of other
     -------                                                           
     documents and agreements are intended to be summaries only and do not
     provide comprehensive descriptions of the terms and conditions contained in
     such documents and agreements.

                                      -75-

 
           7.2.2.   Material Agreements.  The Company has previously furnished
                   -------------------                                          
     to the Lenders correct and complete copies, including all exhibits,
     schedules and amendments thereto, of the agreements and instruments, each
     as in effect on the date hereof, listed in Exhibit 7.2.2, which constitute
     all agreements and instruments material to the Parent and its Subsidiaries
     on a Consolidated basis (the "Material Agreements").
                                    -------------------   

     7.3.  Agreements Relating to Financing Debt, Investments, etc.  Exhibit 
           -------------------------------------------------------      
7.3, as from time to time hereafter supplemented in accordance with Sections
6.4.1 and 6.4.2, sets forth:

           7.3.1.   The amounts (as of the dates indicated in Exhibit 7.3, as so
     supplemented) of all Financing Debt of the Company and its Subsidiaries and
     all agreements which relate to such Financing Debt.

           7.3.2.   All Liens and Guarantees with respect to such Financing
     Debt.

           7.3.3.   All agreements which directly or indirectly require the
     Company or any Subsidiary to make any Investment.

           7.3.4.   Material license agreements with respect to the assets of
     the Company and its Subsidiaries, including the parties thereto and the
     expiration dates thereof.

           7.3.5.   All trademarks, tradenames, service marks, service names and
     patents owned by the Company and its Subsidiaries that are registered with
     the federal Patent and Trademark Office (or with respect to which
     applications for such registration have been filed).

           7.3.6.   All copyrights owned by the Company and its Subsidiaries
     that are registered with the federal Copyright Office.

           7.3.7.   All financial institutions (other than the Lenders) with
     whom bank and deposit accounts are owned by the Company and its
     Subsidiaries.

The Company has furnished the Lenders correct and complete copies of any
agreements described above in this Section 7.3 requested by the Required
Lenders.

     7.4.  Changes in Condition.  Except as otherwise disclosed in writing to 
           --------------------                                        
the Lenders prior to the date hereof, since December 31, 1997, no Material
Adverse Change has occurred and between December 31, 1997 and the date hereof,
neither the Company nor any Subsidiary of the Company has entered into any
material transaction outside the ordinary course of business except for the
transactions contemplated by this Agreement and the Material Agreements.
 

                                      -76-

 
     7.5.  Title to Assets.  The Company, its Subsidiaries and the Parent have
           ---------------                                                    
good title to all assets necessary for or used in the operations of their
business as now conducted by them and reflected in the most recent balance sheet
referred to in Section 7.2.1 (or the balance sheet most recently furnished to
the Lenders pursuant to Sections 6.4.1 or 6.4.2), and to all assets acquired
subsequent to the date of such balance sheet, subject to no Liens except for
Liens permitted by Section 6.8 and except for assets disposed of as permitted by
Section 6.11.

     7.6.  Operations in Conformity With Law, etc.  The operations of the
           --------------------------------------                        
Company, its Subsidiaries and the Parent as now conducted or proposed to be
conducted are not in violation of, nor is the Company, its Subsidiaries or the
Parent in default under, any Legal Requirement presently in effect, except for
such violations and defaults as do not and will not, in the aggregate, result,
or create a material risk of resulting, in any Material Adverse Change.  Neither
the Company, any of its Subsidiaries nor the Parent has received notice of any
such violation or default or has knowledge of any basis on which the operations
of the Company, any of its Subsidiaries or the Parent, as now conducted and as
currently proposed to be conducted after the date hereof, would be held so as to
violate or to give rise to any such violation or default.

     7.7.  Litigation.  No litigation, at law or in equity, or any proceeding
           ----------                                                        
before any court, board or other governmental or administrative agency or any
arbitrator is pending or, to the knowledge of the Company or any Guarantor,
threatened which involves any material risk of any final judgment, order or
liability which, after giving effect to any applicable insurance, has resulted,
or creates a material risk of resulting, in any Material Adverse Change or which
seeks to enjoin the consummation, or which questions the validity, of any of the
transactions contemplated by this Agreement or any other Credit Document.  No
judgment, decree or order of any court, board or other governmental or
administrative agency or any arbitrator has been issued against or binds the
Company or any of its Subsidiaries which has resulted, or creates a material
risk of resulting, in any Material Adverse Change.

     7.8.  Authorization and Enforceability.  Each of the Company and each other
           --------------------------------                                     
Obligor has taken all corporate action required to execute, deliver and perform
this Agreement and each other Credit Document to which it is party.  No consent
of stockholders of the Company which has not been obtained is necessary in order
to authorize the execution, delivery or performance of this Agreement or any
other Credit Document to which the Company is party.  Each of this Agreement and
each other Credit Document constitutes the legal, valid and binding obligation
of each Obligor party thereto and is enforceable against such Obligor in
accordance with its terms.

     7.9.  No Legal Obstacle to Agreements.  Neither the execution and delivery
           -------------------------------                                     
of this Agreement or any other Credit Document, nor the making of any borrowings
hereunder, nor the guaranteeing of the Credit Obligations, nor the securing of
the Credit Obligations with the 

                                      -77-

 
Credit Security, nor the consummation of any transaction referred to in or
contemplated by this Agreement or any other Credit Document, nor the fulfillment
of the terms hereof or thereof or of any other agreement, instrument, deed or
lease contemplated by this Agreement or any other Credit Document, has
constituted or resulted in or will constitute or result in:

          (1)   any breach or termination of the provisions of any agreement,
     instrument, deed or lease to which the Company, any of its Subsidiaries,
     the Parent or any other Obligor is a party or by which it is bound, or of
     the Charter or By-laws of the Company, any of its Subsidiaries, the Parent
     or any other Obligor;

          (2)   the violation of any law, statute, judgment, decree or
     governmental order, rule or regulation applicable to the Company, any of
     its Subsidiaries, the Parent or any other Obligor;

          (3)   the creation under any agreement, instrument, deed or lease of
     any Lien (other than Liens on the Credit Security which secure the Credit
     Obligations) upon any of the assets of the Company, any of its
     Subsidiaries, the Parent or any other Obligor; or

          (4)   any redemption, retirement or other repurchase obligation of the
     Company, any of its Subsidiaries, the Parent or any other Obligor under any
     Charter, By-law, agreement, instrument, deed or lease.

No approval, authorization or other action by, or declaration to or filing with,
any governmental or administrative authority or any other Person which has not
been obtained is required to be obtained or made by the Company, any of its
Subsidiaries or any other Obligor in connection with the execution, delivery and
performance of this Agreement, the Notes or any other Credit Document, the
transactions contemplated hereby or thereby, the making of any borrowing
hereunder, the guaranteeing of the Credit Obligations or the securing of the
Credit Obligations with the Credit Security (other than filings necessary to
perfect the Agent's security interest in the Credit Security).

     7.10.  Defaults.  Neither the Company nor any of its Subsidiaries nor the
            --------                                                          
Parent is in default under any provision of its Charter or By-laws or of this
Agreement or any other Credit Document.  Neither the Company nor any of its
Subsidiaries nor the Parent is in default under any provision of any agreement,
instrument, deed or lease to which it is party or by which it or its property is
bound so as to result, or create a material risk of resulting, in any Material
Adverse Change.  Neither the Company nor any of its Subsidiaries nor the Parent
has violated any law, judgment, decree or governmental order, rule or
regulation, in each case so as to result, or create a material risk of
resulting, in any Material Adverse Change.

                                      -78-

 
     7.11.  Licenses, etc.  The Company and its Subsidiaries have all patents,
            -------------                                                     
patent applications, patent licenses, patent rights, trademarks, trademark
rights, trade names, trade name rights, copyrights, licenses, franchises,
permits, authorizations and other rights as are necessary for the conduct of the
business of the Company and its Subsidiaries as now conducted by them and the
lack of which would result, or create a material risk of resulting, in any
Material Adverse Change.  All of the foregoing are in full force and effect in
all material respects, and each of the Company and its Subsidiaries is in
substantial compliance with the foregoing without any known conflict with the
valid rights of others which has resulted, or creates a material risk of
resulting, in any Material Adverse Change.  No event has occurred which permits,
or after notice or lapse of time or both would permit, the revocation or
termination of any such license, franchise or other right or which affects the
rights of any of the Company and its Subsidiaries thereunder so as to result, or
to create a material risk of resulting, in any Material Adverse Change.  No
litigation or other proceeding or dispute exists with respect to the validity
or, where applicable, the extension or renewal, of any of the foregoing which
has resulted, or creates a material risk of resulting, in any Material Adverse
Change.
 
     7.12.  Tax Returns.  Each of the Company and its Subsidiaries has filed all
            -----------                                                         
material tax and information returns which are required to be filed by it and
has paid, or made adequate provision for the payment of, all taxes which have or
may become due pursuant to such returns or to any assessment received by it,
other than taxes and assessments being contested by the Company and its
Subsidiaries in good faith by appropriate proceedings and for which adequate
reserves have been taken in accordance with GAAP.  Neither the Company nor any
of its Subsidiaries knows of any material additional assessments or any basis
therefor.  The Company reasonably believes that the charges, accruals and
reserves on the books of the Company and its Subsidiaries in respect of taxes or
other governmental charges are adequate.

     7.13.  Certain Business Representations.
            -------------------------------- 

          7.13.1.  Labor Relations.  No dispute or controversy between the 
                   ---------------
Company or any of its Subsidiaries and any of their respective employees has
resulted, or is reasonably likely to result, in any Material Adverse Change, and
neither the Company nor any of its Subsidiaries anticipates that its
relationships with its unions or employees will result, or are reasonably likely
to result, in any Material Adverse Change. The Company and each of its
Subsidiaries is in compliance in all material respects with all federal and
state laws with respect to (a) non-discrimination in employment with which the
failure to comply, in the aggregate, has resulted, or creates a material risk of
resulting, in a Material Adverse Change and (b) the payment of wages.

                                      -79-

 
          7.13.2.  Antitrust.  Each of the Company and its Subsidiaries is in
                   ---------                                                 
compliance in all material respects with all federal and state antitrust laws
relating to its business and the geographic concentration of its business.

          7.13.3.  Tower Sites.  At least a majority of the Towers that do not
                   -----------                                                
constitute Pledged Towers are constructed so as to be capable of being moved
from their present locations and except to the extent recordation of any
renewal, extension, amendment, assignment or other instrument in connection with
any lease of real property in the applicable public records may be required in
order to permit removal of a Tower, the Company and its Subsidiaries have the
right to remove such Towers from their present locations.

          7.13.4.  Real Property Leases.  The present and contemplated use of 
                   --------------------
the real property owned or leased by the Company for the operation of Towers is
in compliance in all material respects with all applicable zoning ordinances and
regulations and other laws and regulations where failure so to comply would
result, or create reasonable risk of resulting, in a Material Adverse Change.
Each Lease is in full force and effect, the Company or one of its Subsidiaries
has all rights of the lessee thereunder, there has been no default in the
performance of any of its terms or conditions by any party thereto, and no
claims of default have been asserted with respect thereto where such default
would result, or create a reasonable risk of resulting, in a Material Adverse
Change.

          7.13.5.  FCC and FAA Matters. The Company (a) has duly and timely 
                   ------------------- 
filed all material reports, registrations and other material filings, if any,
which are required to be filed by it or any of its Subsidiaries under the
Communications Act or any other applicable law, rule or regulation of any
governmental authority, including the FCC and the FAA, the non-filing of which
would not result, or be reasonably likely to result, in a Material Adverse
Change, and (b) is in compliance with all such laws, rules, regulations and
ordinances, including those promulgated by the FCC and the FAA, to the extent
the noncompliance with which would result, or be reasonably likely to result, in
a Material Adverse Change. All information provided by or on behalf of the
Company or any Affiliate in any material filing, if any, with the FCC and the
FAA relating to the business of the Company and its Subsidiaries was, to the
knowledge of such Person at the time of filing, complete and correct in all
material respects when made, and the FCC and the FAA have been notified of any
substantial or significant changes in such information as may be required in
accordance with applicable Legal Requirements.

          7.13.6.  Year 2000 Issues.  Based on a review of the operations of the
                   ----------------                                             
Company and its Subsidiaries as they relate to the processing, storage and
retrieval of data, the Company does not believe that a Material Adverse Change
is reasonably likely 

                                      -80-

 
to occur as a result of computer software and hardware that will not function
with respect to periods commencing January 1, 2000 at least as effectively as
with respect to periods ending on or prior to December 31, 1999.

     7.14.  Environmental Regulations.
            ------------------------- 

          7.14.1.  Environmental Compliance.  To the knowledge of the Company 
                   ------------------------
and its Subsidiaries, each of the Company and its Subsidiaries is in compliance
in all material respects with the Clean Air Act, the Federal Water Pollution
Control Act, the Marine Protection Research and Sanctuaries Act, RCRA, CERCLA
and any other Environmental Law in effect in any jurisdiction in which any
properties of the Company or any of its Subsidiaries are located or where any of
them conducts its business, and with all applicable published rules and
regulations (and applicable standards and requirements) of the federal
Environmental Protection Agency and of any similar agencies in states or foreign
countries in which the Company or its Subsidiaries conducts its business other
than those which in the aggregate have not resulted, and do not create a
material risk of resulting, in a Material Adverse Change.

          7.14.2.  Environmental Litigation.  No suit, claim, action or 
                   ------------------------
proceeding of which the Company or any of its Subsidiaries has been given notice
or otherwise has knowledge is now pending before any court, governmental agency
or board or other forum, or to the Company's or any of its Subsidiaries
knowledge, threatened by any Person (nor to the Company's or any of its
Subsidiaries' knowledge, does any factual basis exist therefor) for, and neither
the Company nor any of its Subsidiaries have received written correspondence
from any federal, state or local governmental authority with respect to:

          (1)   noncompliance by the Company or any of its Subsidiaries with any
     Environmental Law;

          (2)   personal injury, wrongful death or other tortious conduct
     relating to materials, commodities or products used, generated, sold,
     transferred or manufactured by the Company or any of its Subsidiaries
     (including products made of, containing or incorporating asbestos, lead or
     other Hazardous Material, commodities or toxic substances); or

          (3)   the release into the environment by the Company or any of its
     Subsidiaries of any Hazardous Material generated by the Company or any of
     its Subsidiaries whether or not occurring at or on a site owned, leased or
     operated by the Company or any of its Subsidiaries.

                                      -81-

 
          7.14.3.  Hazardous Material.  To the knowledge of the Company and its
                   ------------------                                          
     Subsidiaries, any waste disposal or dump sites at which Hazardous Material
     generated by either the Company or any of its Subsidiaries has been
     disposed of directly by the Company or any of its Subsidiaries and all
     independent contractors to whom the Company or any of its Subsidiaries have
     delivered Hazardous Material, or to the Company's or any of its
     Subsidiaries' knowledge, where Hazardous Material finally came to be
     located, has not resulted, and does not create a material risk of
     resulting, in a Material Adverse Change.

          7.14.4.  Environmental Condition of Properties.  To the knowledge of 
                   -------------------------------------
     the Company and its Subsidiaries, none of the properties owned or leased by
     the Company or any of its Subsidiaries has been used as a treatment,
     storage or disposal site, other than as disclosed in Exhibit 7.14. Except
     as disclosed in Exhibit 7.14, to the knowledge of the Company and its
     Subsidiaries, no Hazardous Material is present in any real property
     currently or formerly owned or operated by the Company or any of its
     Subsidiaries except that which has not resulted, and does not create a
     material risk of resulting, in a Material Adverse Change.

     7.15. Pension Plans.  Each Plan (other than a Multiemployer Plan) and, to
           -------------                                                      
the knowledge of the Company and its Subsidiaries, each Multiemployer Plan is in
material compliance with the applicable provisions of ERISA and the Code.  Each
Multiemployer Plan and each Plan that constitutes a "defined benefit plan" (as
defined in ERISA) are set forth in Exhibit 7.15.  Each ERISA Group Person has
met all of the funding standards applicable to all Plans that are not
Multiemployer Plans, and no condition exists which would permit the institution
of proceedings to terminate any Plan that is not a Multiemployer Plan under
section 4042 of ERISA.  To the best knowledge of the Company and each
Subsidiary, no Plan that is a Multiemployer Plan is currently insolvent or in
reorganization or has been terminated within the meaning of ERISA.

     7.16. Government Regulation; Margin Stock.
           ----------------------------------- 

          7.16.1. Government Regulation.  Neither the Company nor any of its
                  ---------------------                                     
     Subsidiaries, nor any Person controlling the Company or any of its
     Subsidiaries or under common control with the Company or any of its
     Subsidiaries, is subject to regulation under the Public Utility Holding
     Company Act of 1935, the Federal Power Act, the Investment Company Act, the
     Interstate Commerce Act or any statute or regulation which regulates the
     incurring by the Company or any of its Subsidiaries of Financing Debt as
     contemplated by this Agreement and the other Credit Documents.

          7.16.2. Margin Stock.  Neither the Company nor any of its Subsidiaries
                  ------------                                                  
     owns any Margin Stock.

                                      -82-

 
     7.17. Disclosure.  Neither this Agreement nor any other Credit Document to
           ----------                                                          
be furnished to the Lenders by or on behalf of the Company or any of its
Subsidiaries in connection with the transactions contemplated hereby or by such
Credit Document contains any untrue statement of material fact or omits to state
a material fact necessary in order to make the statements contained herein or
therein not misleading in light of the circumstances under which they were made.
No fact is actually known to the Company or any of its Subsidiaries which has
resulted, or in the future (so far as the Company or any of its Subsidiaries can
reasonably foresee) will result, or creates a material risk of resulting, in any
Material Adverse Change, except to the extent that present or future general
economic conditions may result in a Material Adverse Change.

 8.  DEFAULTS.
     -------- 

     8.1. Events of Default.  The following events are referred to as "Events of
          -----------------                                            ---------
Default":
- -------  

          8.1.1. Payment.  The Company shall fail to make any payment in respect
                 -------                                                        
     of: (a) interest or any fee on or in respect of any of the Credit
     Obligations owed by it as the same shall become due and payable, and such
     failure shall continue for a period of three Banking Days, or (b) any
     Credit Obligation with respect to payments made by any Letter of Credit
     Issuer under any Letter of Credit or any draft drawn thereunder within
     three Banking Days after demand therefor by such Letter of Credit Issuer or
     (c) principal of any of the Credit Obligations owed by it as the same shall
     become due, whether at maturity or by acceleration or otherwise.

          8.1.2. Specified Covenants.  The Company or any of its Subsidiaries or
                 -------------------                                            
     the Parent shall fail to perform or observe any of the provisions of
     Section 6.4.6 or Sections 6.5 through 6.22 applicable to it.

          8.1.3. Other Covenants.  The Company, any of its Subsidiaries or any
                 ---------------                                              
     other Obligor shall fail to perform or observe any other covenant,
     agreement or provision to be performed or observed by it under this
     Agreement or any other Credit Document, and such failure shall not be
     rectified or cured to the satisfaction of the Required Lenders within 30
     days after the earlier of (a) notice thereof by the Agent to the Company or
     (b) a Financial Officer shall have actual knowledge thereof.

          8.1.4. Representations and Warranties.  Any representation or warranty
                 ------------------------------                                 
     of or with respect to the Company, any of its Subsidiaries or any other
     Obligor made to the Lenders or the Agent in or pursuant to this Agreement
     or any other Credit Document, or in any financial statement, report,
     notice, mortgage, assignment, UCC financing statement or certificate
     delivered to the Agent or any of the Lenders by the Company, any of its
     Subsidiaries or any other Obligor in connection herewith or therewith,
     shall be false in any material respect on the date as of which it was made.

                                      -83-

 
          8.1.5. Cross Default, etc.
                 ------------------ 

          (1)   The Company or any of its Subsidiaries or the Parent shall fail
     to make any payment when due (after giving effect to any applicable grace
     periods) in respect of any Financing Debt (other than the Credit
     Obligations) outstanding in an aggregate amount of principal (whether or
     not due) and accrued interest exceeding $1,000,000;

          (2)   the Company or any of its Subsidiaries or the Parent shall fail
     to perform or observe the terms of any agreement or instrument relating to
     such Financing Debt, and such failure shall continue, without having been
     duly cured, waived or consented to, beyond the period of grace, if any,
     specified in such agreement or instrument, and such failure shall permit
     the acceleration of such Financing Debt;

          (3)   all or any part of such Financing Debt of the Company or any of
     its Subsidiaries or the Parent shall be accelerated or shall become due or
     payable prior to its stated maturity (except with respect to voluntary
     prepayments thereof) for any reason whatsoever;

          (4)   any Lien on any property of the Company or any of its
     Subsidiaries or the Parent securing any such Financing Debt shall be
     enforced by foreclosure or similar action; or

          (5)   any holder of any such Financing Debt shall exercise any right
     of rescission with respect  to the issuance thereof or put, mandatory
     prepayment or repurchase rights against any Obligor with respect to such
     Financing Debt (other than any such rights that may be satisfied with
     "payment in kind" notes or other similar securities).

          8.1.6.  Ownership; Liquidation; etc.  Except as permitted by 
                  ---------------------------                                 
     Section 6.11:

          (1)   the Company shall cease to own, directly or indirectly, all the
     capital stock of its Subsidiaries, except to the extent permitted by
     Section 6.12.1; or

          (2)   prior to the initial closing of an initial underwritten public
     offering of Parent Stock registered under the Securities Act, Steven E.
     Bernstein, ABS Capital Partners II, L.P., ABS Employees' Venture Fund
     Limited Partnership, TA Venture Investors Limited Partnership, Advent VII,
     L.P., Advent Atlantic and Pacific III, LP and various members of the
     Hillman family (or trusts established for their benefit) shall cease to
     own, beneficially and of record, at least a majority of the voting stock
     and of the total equity capital of the Parent; or

                                      -84-

 
          (3)   the Parent shall cease to own, directly or indirectly, all the
     capital stock of the Company; or

          (4)   Steven E. Bernstein shall cease to be actively involved in the
     executive management of the Company and a replacement reasonably
     satisfactory to the Required Lenders has not been hired within six months
     thereof; or

          (5)   the Company or any of its Subsidiaries or any other Obligor
     shall initiate any action to dissolve, liquidate or otherwise terminate its
     existence.

          8.1.7. Enforceability, etc.  Any Credit Document shall cease for any
                 -------------------                                          
reason (other than the scheduled termination thereof in accordance with its
terms) to be enforceable in accordance with its terms or in full force and
effect; or any party to any Credit Document shall so assert in a judicial or
similar proceeding; or the security interests created by this Agreement or any
other Credit Documents shall cease to be enforceable and of the same effect and
priority purported to be created hereby.

          8.1.8. Judgments.  A final judgment (a) which, with other outstanding
                 ---------                                                     
final judgments against the Company and its Subsidiaries, exceeds an aggregate
of $1,000,000 in excess of applicable insurance coverage shall be rendered
against the Company or any of its Subsidiaries, or (b) which grants injunctive
relief that results, or creates a material risk of resulting, in a Material
Adverse Change and in either case if (i) within 60 days after entry thereof,
such judgment shall not have been discharged or execution thereof stayed pending
appeal or (ii) within 60 days after the expiration of any such stay, such
judgment shall not have been discharged.

          8.1.9. ERISA.  Any "reportable event" (as defined in section 4043 of
                 -----                                                        
ERISA) shall have occurred that reasonably could be expected to result in
termination of a Plan or the appointment by the appropriate United States
District Court of a trustee to administer any Plan or the imposition of a Lien
in favor of a Plan; or any ERISA Group Person shall fail to pay when due amounts
aggregating in excess of $1,000,000 which it shall have become liable to pay to
the PBGC or to a Plan under Title IV of ERISA; or notice of intent to terminate
a Plan shall be filed under Title IV of ERISA by any ERISA Group Person or
administrator; or the PBGC shall institute proceedings under Title IV of ERISA
to terminate or to cause a trustee to be appointed to administer any Plan or a
proceeding shall be instituted by a fiduciary of any Plan against any ERISA
Group Person to enforce section 515 or 4219(c)(5) of ERISA and such proceeding
shall not have been dismissed within 30 days thereafter; or a condition shall
exist by reason of which the PBGC would be entitled to obtain a decree
adjudicating that any Plan must be terminated.

                                      -85-

 
          8.1.10.  Bankruptcy, etc.  The Company, any of its Subsidiaries or any
                   ---------------                                              
     other Obligor shall:

          (1)   commence a voluntary case under the Bankruptcy Code or
     authorize, by appropriate proceedings of its board of directors or other
     governing body, the commencement of such a voluntary case;

          (2)   (i) have filed against it a petition commencing an involuntary
     case under the Bankruptcy Code that shall not have been dismissed within 60
     days after the date on which such petition is filed, or (ii) file an answer
     or other pleading within such 60-day period admitting or failing to deny
     the material allegations of such a petition or seeking, consenting to or
     acquiescing in the relief therein provided, or (iii) have entered against
     it an order for relief in any involuntary case commenced under the
     Bankruptcy Code;

          (3)   seek relief as a debtor under any applicable law, other than the
     Bankruptcy Code, of any jurisdiction relating to the liquidation or
     reorganization of debtors or to the modification or alteration of the
     rights of creditors, or consent to or acquiesce in such relief;

          (4)   have entered against it an order by a court of competent
     jurisdiction (i) finding it to be bankrupt or insolvent, (ii) ordering or
     approving its liquidation or reorganization as a debtor or any modification
     or alteration of the rights of its creditors or (iii) assuming custody of,
     or appointing a receiver or other custodian for, all or a substantial
     portion of its property; or

          (5)   make an assignment for the benefit of, or enter into a
     composition with, its creditors, or appoint, or consent to the appointment
     of, or suffer to exist a receiver or other custodian for, all or a
     substantial portion of its property.

     8.2. Certain Actions Following an Event of Default.  If any one or more
          ---------------------------------------------                     
Events of Default shall occur, then in each and every such case:

          8.2.1. Terminate Obligation to Extend Credit.  Upon written request of
                 -------------------------------------                          
     the Required Lenders, the Agent shall terminate the obligations of the
     Lenders to make any further extensions of credit under the Credit Documents
     by furnishing notice of such termination to the Company; provided, however,
                                                              --------  -------
     that if a Bankruptcy Default shall have occurred, the obligations of the
     Lenders to make any further extensions of credit under the Credit Documents
     shall automatically terminate.

          8.2.2. Specific Performance; Exercise of Rights.  Upon written request
                 ----------------------------------------                       
     of the Required Lenders, the Agent shall proceed to protect and enforce the
     Lenders' rights by suit in equity, action at law and/or other appropriate
     proceeding, either for 

                                      -86-

 
     specific performance of any covenant or condition contained in this
     Agreement or any other Credit Document (other than Interest Rate Protection
     Agreements) or in any instrument or assignment delivered to the Lenders
     pursuant to this Agreement or any other Credit Document (other than
     Interest Rate Protection Agreements), or in aid of the exercise of any
     power granted in this Agreement or any other Credit Document (other than
     Interest Rate Protection Agreements) or any such instrument or assignment.

          8.2.3. Acceleration.  Upon written request of the Required Lenders, 
                 ------------  
     the Agent shall by notice in writing to the Company (a) declare all or any
     part of the unpaid balance of the Credit Obligations (other than amounts
     under Interest Rate Protection Agreements) then outstanding to be
     immediately due and payable, and (b) require the Company immediately to
     deposit with the Agent in cash an amount equal to the then Letter of Credit
     Exposure (which cash shall be held and applied as provided in Section 4.5),
     and thereupon such unpaid balance or part thereof and such amount equal to
     the Letter of Credit Exposure shall become so due and payable without
     presentation, protest or further demand or notice of any kind, all of which
     are hereby expressly waived; provided, however, that if a Bankruptcy
                                  --------  -------
     Default shall have occurred, the unpaid balance of the Credit Obligations
     (other than amounts under Interest Rate Protection Agreements) shall
     automatically become immediately due and payable.

          8.2.4. Enforcement of Payment; Credit Security; Setoff.  Upon written
                 -----------------------------------------------               
     request of the Required Lenders, the Agent shall proceed to enforce payment
     of the Credit Obligations in such manner as it may elect, to cancel, or
     instruct other Letter of Credit Issuers to cancel, any outstanding Letters
     of Credit which permit the cancellation thereof and to realize upon any and
     all rights in the Credit Security. The Lenders may offset and apply toward
     the payment of the Credit Obligations (and/or toward the curing of any
     Event of Default) any Indebtedness from the Lenders to the respective
     Obligors, including any Indebtedness represented by deposits in any account
     maintained with the Lenders, regardless of the adequacy of any security for
     the Credit Obligations. The Lenders shall have no duty to determine the
     adequacy of any such security in connection with any such offset.

          8.2.5. Cumulative Remedies.  To the extent not prohibited by 
                 -------------------
     applicable law which cannot be waived, all of the Lenders' rights hereunder
     and under each other Credit Document shall be cumulative.

     8.3. Annulment of Defaults.  Once an Event of Default has occurred, such
          ---------------------                                              
Event of Default shall be deemed to exist and be continuing for all purposes of
the Credit Documents (other than Interest Rate Protection Agreements) until the
Required Lenders or the Agent (with the consent of the Required Lenders) shall
have waived such Event of Default in writing, stated in writing that the same
has been cured to such Lenders' reasonable satisfaction or entered into an
amendment to this Agreement which by its express terms cures such Event of
Default, at 

                                      -87-

 
which time such Event of Default shall no longer be deemed to exist or to have
continued. No such action by the Lenders or the Agent shall extend to or affect
any subsequent Event of Default or impair any rights of the Lenders upon the
occurrence thereof. The making of any extension of credit during the existence
of any Default or Event of Default shall not constitute a waiver thereof.

     8.4. Waivers.  To the extent that such waiver is not prohibited by the
          -------                                                          
provisions of applicable law that cannot be waived, each of the Company and the
other Obligors waives:

          (1)   all presentments, demands for performance, notices of
     nonperformance (except to the extent required by this Agreement or any
     other Credit Document), protests, notices of protest and notices of
     dishonor;

          (2)   any requirement of diligence or promptness on the part of the
     Agent or any Lender in the enforcement of its rights under this Agreement,
     the Notes or any other Credit Document;

          (3)   any and all notices of every kind and description which may be
     required to be given by any statute or rule of law; and

          (4)  any defense (other than indefeasible payment in full) which it
     may now or hereafter have with respect to its liability under this
     Agreement, the Notes or any other Credit Document or with respect to the
     Credit Obligations.

 9.  EXPENSES; INDEMNITY.
     ------------------- 

     9.1  Expenses.  Whether or not the transactions contemplated hereby shall
          --------                                                            
be consummated, the Company will pay:

          (1)   all reasonable expenses of the Agent and the Syndication Agent
     (including the out-of-pocket expenses related to forming the group of
     Lenders and reasonable fees and disbursements of the counsel to the Agent
     and the Syndication Agent) in connection with the negotiation, preparation
     and duplication of this Agreement and each other Credit Document,
     examinations by and reports of the Agent's commercial financial examiners,
     fixed asset appraisers and environmental consultants, the transactions
     contemplated hereby and thereby and amendments, waivers, consents and other
     operations hereunder and thereunder;

          (2)   all recording and filing fees and transfer and documentary stamp
     and similar taxes at any time payable in respect of this Agreement, any
     other Credit Document, any Credit Security or the incurrence of the Credit
     Obligations; and

                                      -88-

 
          (3)   all other reasonable expenses incurred by the Lenders or the
     holder of any Credit Obligation in connection with the enforcement of any
     rights hereunder or under any other Credit Document or any work-out
     negotiations relating to the Credit Obligations, including costs of
     collection and reasonable attorneys' fees and expenses.

     9.2. General Indemnity.  The Company shall indemnify the Lenders and the
          -----------------                                                  
Agent and hold them harmless from any liability, loss or damage resulting from
the violation by the Company of Section 2.4.  In addition, the Company shall
indemnify each Lender, the Agent, the Syndication Agent, each of the Lenders' or
the Agent's or the Syndication Agent's directors, officers, employees, agents,
attorneys, accountants, consultants and each Person, if any, who controls any
Lender or the Agent or the Syndication Agent (each Lender, the Agent, the
Syndication Agent and each of such directors, officers, employees, agents,
attorneys, accountants, consultants and control Persons is referred to as an
                                                                            
"Indemnified Party") and hold each of them harmless from and against any and all
 -----------------                                                              
claims, damages, liabilities and reasonable expenses (including reasonable fees
and disbursements of counsel with whom any Indemnified Party may consult in
connection therewith and all reasonable expenses of litigation or preparation
therefor) which any Indemnified Party may incur or which may be asserted against
any Indemnified Party in connection with (a) the Indemnified Party's compliance
with or contest of any subpoena or other process issued against it in any
proceeding involving the Company or any of its Subsidiaries or their Affiliates,
(b) any litigation or investigation involving the Company, any of its
Subsidiaries or their Affiliates, or any officer, director or employee thereof,
(c) the existence or exercise of any security rights with respect to the Credit
Security in accordance with the Credit Documents, or (d) this Agreement, any
other Credit Document or any transaction contemplated hereby or thereby;
provided, however, that the foregoing indemnity shall not apply to litigation
- --------  -------                                                            
commenced by the Company against the Lenders or the Agent or the Syndication
Agent which seeks enforcement of any of the rights of the Company hereunder or
under any other Credit Document and is determined adversely to the Lenders or
the Agent or the Syndication Agent in a final nonappealable judgment or to the
extent such claims, damages, liabilities and expenses result from a Lender's or
the Agent's or the Syndication Agent's gross negligence or willful misconduct.

     9.3. Indemnity With Respect to Letters of Credit.  The Company shall
          -------------------------------------------                    
indemnify each Letter of Credit Issuer and its correspondents and hold each of
them harmless from and against any and all claims, losses, liabilities, damages
and reasonable expenses (including reasonable attorneys' fees) arising from or
in connection with any Letter of Credit, including any such claim, loss,
liability, damage or expense arising out of any transfer, sale, delivery,
surrender or endorsement of any invoice, bill of lading, warehouse receipt or
other document at any time held by the Agent, any other Letter of Credit Issuer
or held for their respective accounts by any of their correspondents, in
connection with any Letter of Credit, except to the extent such claims, losses,
liabilities, damages and expenses result from gross negligence or willful
misconduct on the part of the Agent or any other Letter of Credit Issuer.

                                      -89-

 
10. OPERATIONS; AGENT.
    ----------------- 

    10.1.  Interests in Credits.  The Percentage Interest of each Lender in the
           --------------------                                                
Loan and Letters of Credit, and the related Commitments, shall be computed based
on the maximum principal amount for each Lender as set forth in the Register, as
from time to time in effect. The current Percentage Interests are set forth in
Exhibit 10.1, which may be updated by the Agent from time to time to conform to
the Register.

    10.2.  Agent's Authority to Act, etc.  Each of the Lenders appoints and
           -----------------------------                                   
authorizes BankBoston to act for the Lenders as the Lenders' Agent in connection
with the transactions contemplated by this Agreement and the other Credit
Documents (other than Interest Rate Protection Agreements) on the terms set
forth herein and therein.  In acting hereunder, the Agent is acting for its own
account to the extent of its Percentage Interest and for the account of each
other Lender to the extent of the Lenders' respective Percentage Interests, and
all action in connection with the enforcement of, or the exercise of any
remedies (other than the Lenders' rights of set-off as provided in Section 8.2.4
or in any Credit Document) in respect of the Credit Obligations and Credit
Documents shall be taken by the Agent.  In particular, the Agent is specifically
authorized to execute and deliver on behalf of the Lenders the Borrower
Assumption Agreement.

    10.3.  Company to Pay Agent, etc.  The Company and each Guarantor shall be
           -------------------------                                          
fully protected in making all payments in respect of the Credit Obligations
(other than payments under Interest Rate Protection Agreements) to the Agent, in
relying upon consents, modifications and amendments executed by the Agent
purportedly on the Lenders' behalf, and in dealing with the Agent as herein
provided.  The Agent may charge the accounts of the Company, on the dates when
the amounts thereof become due and payable, with the amounts of the principal of
and interest on the Loan, any amounts paid by the Letter of Credit Issuers to
third parties under Letters of Credit or drafts presented thereunder, commitment
fees, Letter of Credit fees and all other fees and amounts owing under any
Credit Document (other than Interest Rate Protection Agreements).

    10.4.  Lender Operations for Advances, Letters of Credit, etc.
           ------------------------------------------------------ 
           10.4.1.  Advances. On each Closing Date, each Lender shall advance to
                    --------                   
    the Agent in immediately available funds such Lender's Percentage Interest
    in the portion of the Loan advanced on such Closing Date prior to 12:00 noon
    (Boston time). If such funds are not received at such time, but all
    applicable conditions set forth in Section 5 have been satisfied, each
    Lender authorizes and requests the Agent to advance for the Lender's
    account, pursuant to the terms hereof, the Lender's respective Percentage
    Interest in such portion of the Loan and agrees to reimburse the Agent in
    immediately available funds for the amount thereof prior to 2:00 p.m.
    (Boston time) on the day any portion of the Loan is advanced hereunder;
    provided, however, that the
    --------  -------

                                      -90-

 
    Agent is not authorized to make any such advance for the account of
    any Lender who has previously notified the Agent in writing that such
    Lender will not be performing its obligations to make further advances
    hereunder; and provided, further, that the Agent shall be under no
                   --------  -------
    obligation to make any such advance.

           10.4.2.  Letters of Credit.  Each of the Lenders authorizes and 
                    -----------------
    requests each Letter of Credit Issuer to issue the Letters of Credit
    provided for in Section 2.3 and to grant each Lender a participation in each
    of such Letters of Credit in an amount equal to its Percentage Interest in
    the amount of each such Letter of Credit. Promptly upon the request of the
    Letter of Credit Issuer, each Lender shall reimburse the Letter of Credit
    Issuer in immediately available funds for such Lender's Percentage Interest
    in the amount of all obligations to third parties incurred by the Letter of
    Credit Issuer in respect of each Letter of Credit and each draft accepted
    under a Letter of Credit to the extent not reimbursed by the Company by 2:00
    p.m. (Boston time) on the Banking Day when due. The Letter of Credit Issuer
    will notify each Lender of the issuance of any Letter of Credit, the amount
    and date of payment of any draft drawn or accepted under a Letter of Credit
    and whether in connection with the payment of any such draft the amount
    thereof was added to the Revolving Loan or was reimbursed by the Company.

           10.4.3.  Agent to Allocate Payments, etc. All payments of principal
                    --------------------------------
    and interest in respect of the extensions of credit made pursuant to this
    Agreement, reimbursement of amounts paid by any Letter of Credit Issuer to
    third parties under Letters of Credit or drafts presented thereunder,
    commitment fees, Letter of Credit fees and other fees under this Agreement
    shall, as a matter of convenience, be made by the Company and the Guarantors
    to the Agent in immediately available funds by noon (Boston time) on any
    Banking Day. The share of each Lender shall be credited to such Lender by
    the Agent in immediately available funds by 2:00 p.m. (Boston time) on such
    Banking Day in such manner that the principal amount of the Credit
    Obligations to be paid shall be paid proportionately in accordance with the
    Lenders' respective Percentage Interests in such Credit Obligations, except
    as otherwise provided in this Agreement. Under no circumstances shall any
    Lender be required to produce or present its Notes as evidence of its
    interests in the Credit Obligations in any action or proceeding relating to
    the Credit Obligations.

           10.4.4  Delinquent Lenders; Nonperforming Lenders. In the event that
                   -----------------------------------------
    any Lender fails to reimburse the Agent pursuant to Sections 10.4.1 and
    10.4.2 for the Percentage Interest of such lender (a "Delinquent Lender") in
                                                          -----------------
    any credit advanced by the Agent pursuant hereto, overdue amounts (the
    "Delinquent Payment") due from the Delinquent Lender to the Agent shall bear
     ------------------
    interest, payable by the Delinquent Lender on demand, at a per annum rate
    equal to (a) the Federal Funds Rate for the first three days overdue and (b)
    the sum of 2% plus the Federal Funds Rate for any longer period. Such
    interest shall be payable to the Agent for its own account for the period

                                      -91-

 
    commencing on the date of the Delinquent Payment and ending on the date the
    Delinquent Lender reimburses the Agent on account of the Delinquent Payment
    (to the extent not paid by any Obligor as provided below) and the accrued
    interest thereon (the "Delinquency Period"), whether pursuant to the
                           ------------------
    assignments referred to below or otherwise. Upon notice by the Agent after
    any such Delinquent Payment is more than three days overdue, the Company
    will pay to the Agent the principal (but not the interest) portion of the
    Delinquent Payment. During the Delinquency Period, in order to make
    reimbursements for the Delinquent Payment and accrued interest thereon, the
    Delinquent Lender shall be deemed to have assigned to the Agent all
    interest, commitment fees and other payments made by the Company under
    Section 3 that would have thereafter otherwise been payable under the Credit
    Documents to the Delinquent Lender. During any other period in which any
    Lender is not performing its obligations to extend credit under Section 2 (a
    "Nonperforming Lender"), the Nonperforming Lender shall be deemed to have
     --------------------
    assigned to each Lender that is not a Nonperforming Lender (a "Performing
                                                                   ----------
    Lender") all principal and other payments made by the Company under Section
    ------
    4 that would have thereafter otherwise been payable under the Credit
    Documents to the Nonperforming Lender. The Agent shall credit a portion of
    such payments to each Performing Lender in an amount equal to the Percentage
    Interest of such Performing Lender in an amount equal to the Percentage
    Interest of such Performing Lender divided by one minus the Percentage
                                                      ----- 
    Interest of the Nonperforming Lender until the respective portions of the
    Loan owed to all the Lenders are the same as the Percentage Interests of the
    Lenders immediately prior to the failure of the Nonperforming Lender to
    perform its obligations under Section 2. The foregoing provisions shall be
    in addition to any other remedies the Agent, the Performing Lenders or the
    Company may have under law or equity against the Delinquent Lender as a
    result of the Delinquent Payment or against the Nonperforming Lender as a
    result of its failure to perform its obligations under Section 2.

    10.5  Sharing of Payments, etc.  Each Lender agrees that (a) if by
          ------------------------                                   
exercising any right of set-off or counterclaim or otherwise, it shall receive
payment of (i) a proportion of the aggregate amount due with respect to its
Percentage Interest in the Loan and Letter of Credit Exposure which is greater
than (ii) the proportion received by any other Lender in respect of the
aggregate amount due with respect to such other Lender's Percentage Interest in
the Loan and Letter of Credit Exposure and (b) if such inequality shall continue
for more than 10 days, the Lender receiving such proportionately greater payment
shall purchase participations in the Percentage Interests in the Loan and Letter
of Credit Exposure held by the other Lenders, and such other adjustments shall
be made from time to time (including rescission of such purchases of
participations in the event the unequal payment originally received is recovered
from such Lender through bankruptcy proceedings or otherwise), as may be
required so that all such payments of principal and interest with respect to the
Loan and Letter of Credit Exposure held by the Lenders shall be shared by the
Lenders pro rata in accordance with their respective Percentage Interests;
                                                                          
provided, however, that this Section 10.5 shall not impair the right of any
- --------  -------                                                          

                                      -92-

 
Lender to exercise any right of set-off or counterclaim it may have and to apply
the amount subject to such exercise to the payment of Indebtedness of any
Obligor other than such Obligor's Indebtedness with respect to the Loan and
Letter of Credit Exposure.  Each Lender that grants a participation in the
Credit Obligations to a Credit Participant shall require as a condition to the
granting of such participation that such Credit Participant agree to share
payments received in respect of the Credit Obligations as provided in this
Section 10.5.  The provisions of this Section 10.5 are for the sole and
exclusive benefit of the Lenders and no failure of any Lender to comply with the
terms hereof shall be available to any Obligor as a defense to the payment of
the Credit Obligations.

    10.6.  Agent's Resignation.  The Agent may resign at any time by giving at
           -------------------                                                
least 60 days' prior written notice of its intention to do so to each of the
Lenders and the Company and upon the appointment by the Required Lenders of a
successor Agent satisfactory to the Company.  If no successor Agent shall have
been so appointed and shall have accepted such appointment within 45 days after
the retiring Agent's giving of such notice of resignation, then the retiring
Agent may with the consent of the Company, which shall not be unreasonably
withheld, appoint a successor Agent which shall be a bank or a trust company
organized under the laws of the United States of America or any state thereof
and having a combined capital, surplus and undivided profit of at least
$200,000,000; provided, however, that any successor Agent appointed under this
              --------  -------                                               
sentence may be removed upon the written request of the Required Lenders, which
request shall also appoint a successor Agent reasonably satisfactory to the
Company.  Upon the appointment of a new Agent hereunder, the term "Agent" shall
for all purposes of this Agreement thereafter mean such successor.  After any
retiring Agent's resignation hereunder as Agent, or the removal hereunder of any
successor Agent, the provisions of this Agreement shall continue to inure to the
benefit of such retiring or removed Agent as to any actions taken or omitted to
be taken by it while it was Agent under this Agreement.

    10.7.  Concerning the Agent.
           -------------------- 

           10.7.1.   Action in Good Faith, etc.  The Agent and its officers,
                     -------------------------                              
    directors, employees and agents shall be under no liability to any of the
    Lenders or to any future holder of any interest in the Credit Obligations
    for any action or failure to act taken or suffered in good faith, and any
    action or failure to act in accordance with an opinion of its counsel shall
    conclusively be deemed to be in good faith. The Agent shall in all cases be
    entitled to rely, and shall be fully protected in relying, on instructions
    given to the Agent by the Required Lenders.

           10.7.2.   No Implied Duties, etc. The Agent shall have and may 
                     ----------------------
    exercise such powers as are specifically delegated to the Agent under this
    Agreement or any other Credit Document together with all other powers
    incidental thereto. The Agent shall have no implied duties to any Person or
    any obligation to take any action under

                                      -93-

 
    this Agreement or any other Credit Document except for action specifically
    provided for in this Agreement or any other Credit Document to be taken by
    the Agent. Before taking any action under this Agreement or any other Credit
    Document, the Agent may request an appropriate specific indemnity reasonably
    satisfactory to it from each Lender in addition to the general indemnity
    provided for in Section 10.10 (but not extending to actions or omissions by
    the Agent constituting gross negligence or willful misconduct). Until the
    Agent has received such specific indemnity, the Agent shall not be obligated
    to take (although it may in its sole discretion take) any such action under
    this Agreement or any other Credit Document. Each Lender confirms that the
    Agent does not have a fiduciary relationship to it under the Credit
    Documents. Each of the Company and each Guarantor confirms that neither the
    Agent nor any other Lender has a fiduciary relationship to it under the
    Credit Documents.

           10.7.3.   Validity, etc. The Agent shall not be responsible to any
                     -------------
    Lender or any future holder of any interest in the Credit Obligations (a)
    for the legality, validity, enforceability or effectiveness of this
    Agreement or any other Credit Document, (b) for any recitals, reports,
    representations, warranties or statements contained in or made in connection
    with this Agreement or any other Credit Document, (c) for the existence or
    value of any assets included in any security for the Credit Obligations, (d)
    for the effectiveness of any Lien purported to be included in the Credit
    Security, (e) for the specification or failure to specify any particular
    assets to be included in the Credit Security, or (f) unless the Agent shall
    have failed to comply with Section 10.7.1, for the perfection of the
    security interests in the Credit Security.

           10.7.4.  Compliance. The Agent shall not be obligated to ascertain or
                    ----------
    inquire as to the performance or observance of any of the terms of this
    Agreement or any other Credit Document; and in connection with any extension
    of credit under this Agreement or any other Credit Document, the Agent shall
    be fully protected in relying on a certificate of the Company as to the
    fulfillment by the Company of any conditions to such extension of credit.

           10.7.5. Employment of Agents and Counsel. The Agent may execute any
                   --------------------------------
    of its duties as Agent under this Agreement or any other Credit Document by
    or through employees, agents and attorneys-in-fact and shall not be
    responsible to any of the Lenders, the Company or any other Obligor for the
    default or misconduct of any such agents or attorneys-in-fact selected by
    the Agent acting in good faith. The Agent shall be entitled to advice of
    counsel concerning all matters pertaining to the agency hereby created and
    its duties hereunder or under any other Credit Document.

          10.7.6. Reliance on Documents and Counsel. The Agent shall be entitled
                  ---------------------------------
    to rely, and shall be fully protected in relying, upon any affidavit,
    certificate, cablegram, consent, instrument, letter, notice, order,
    document, statement, telecopy,

                                      -94-

 
    telegram, telex or teletype message or writing reasonably believed in good
    faith by the Agent to be genuine and correct and to have been signed, sent
    or made by the Person in question, including any telephonic or oral
    statement made by such Person, and, with respect to legal matters, upon an
    opinion or the advice of counsel selected by the Agent.

          10.7.7.   Agent's Reimbursement. Each of the Lenders severally agrees
                    ---------------------
    to reimburse the Agent, pro rata in accordance with such Lender's Percentage
    Interest, for any reasonable expenses not reimbursed by the Company or the
    Guarantors (without limiting the obligation of the Company or the Guarantors
    to make such reimbursement): (a) for which the Agent is entitled to
    reimbursement by the Company or the Guarantors under this Agreement or any
    other Credit Document, and (b) after the occurrence of a Default, for any
    other reasonable expenses incurred by the Agent on the Lenders' behalf in
    connection with the enforcement of the Lenders' rights under this Agreement
    or any other Credit Document; provided, however, that the Agent shall not be
                                  --------  -------
    reimbursed for any such expenses arising as a result of its gross negligence
    or willful misconduct.

    10.8.  Rights as a Lender.  With respect to any credit extended by it
           ------------------                                            
hereunder, BankBoston shall have the same rights, obligations and powers
hereunder as any other Lender and may exercise such rights and powers as though
it were not the Agent, and unless the context otherwise specifies, BankBoston
shall be treated in its individual capacity as though it were not the Agent
hereunder.  Without limiting the generality of the foregoing, the Percentage
Interest of BankBoston shall be included in any computations of Percentage
Interests.  BankBoston and its Affiliates may accept deposits from, lend money
to, act as trustee for and generally engage in any kind of banking or trust
business with the Company, any of its Subsidiaries or any Affiliate of any of
them and any Person who may do business with or own an equity interest in the
Company, any of its Subsidiaries or any Affiliate of any of them, all as if
BankBoston were not the Agent and without any duty to account therefor to the
other Lenders.

    10.9.  Independent Credit Decision. Each of the Lenders acknowledges that
           ---------------------------  
it has independently and without reliance upon the Agent, based on the financial
statements a nd other documents referred to in Section 7.2, on the other
representations and warranties contained herein and on such other information
with respect to the Company and its Subsidiaries as such Lender deemed
appropriate, made such Lender's own credit analysis and decision to enter into
this Agreement and to make the extensions of credit provided for hereunder. Each
Lender represents to the Agent that such Lender will continue to make its own
independent credit and other decisions in taking or not taking action under this
Agreement or any other Credit Document. Each Lender expressly acknowledges that
neither the Agent nor any of its officers, directors, employees, agents,
attorneys-in-fact or Affiliates has made any representations or warranties to
such Lender, and no act by the Agent taken under this Agreement or any other
Credit Document, including any review of the affairs of the Company and its
Subsidiaries,

                                      -95-

 
shall be deemed to constitute any representation or warranty by the Agent.
Except for notices, reports and other documents expressly required to be
furnished to each Lender by the Agent under this Agreement or any other Credit
Document, the Agent shall not have any duty or responsibility to provide any
Lender with any credit or other information concerning the business, operations,
property, condition, financial or otherwise, or creditworthiness of the Company
or any Subsidiary which may come into the possession of the Agent or any of its
officers, directors, employees, agents, attorneys-in-fact or Affiliates.

    10.10.  Indemnification. The Lenders shall severally indemnify the Agent and
            ---------------
its officers, directors, employees, agents, attorneys, accountants, consultants
and controlling Persons (to the extent not reimbursed by the Obligors and
without limiting the obligation of any of the Obligors to do so), pro rata in
accordance with their respective Percentage Interests, from and against any and
all liabilities, obligations, losses, damages, penalties, actions, judgments,
suits, costs, expenses or disbursements of any kind whatsoever which may at any
time be imposed on, incurred by or asserted against the Agent or such Persons
relating to or arising out of this Agreement, any other Credit Document, the
transactions contemplated hereby or thereby, or any action taken or omitted by
the Agent in connection with any of the foregoing; provided, however, that the
                                                   --------  -------          
foregoing shall not extend to actions or omissions which are taken by the Agent
with gross negligence or willful misconduct.

11.  SUCCESSORS AND ASSIGNS; LENDER ASSIGNMENTS AND PARTICIPATIONS. Any
     -------------------------------------------------------------     
reference in this Agreement or any other Credit Document to any of the parties
hereto shall be deemed to include the successors and assigns of such party, and
all covenants and agreements by or on behalf of the Company, the other Obligors,
the Agent or the Lenders that are contained in this Agreement or any other
Credit Document shall bind and inure to the benefit of their respective
successors and assigns; provided, however, that (a) the Company and its
                        --------  -------                              
Subsidiaries may not assign their rights or obligations under this Agreement or
any other Credit Document except for mergers or liquidations permitted by
Section 6.11, and (b) the Lenders shall be not entitled to assign their
respective Percentage Interests in the credits extended hereunder or their
Commitments except as set forth below in this Section 11.

    11.1.  Assignments by Lenders.
           ---------------------- 

           11.1.1.   Assignees and Assignment Procedures.  Each Lender may (a)
                     -----------------------------------                      
    without the consent of the Agent or the Company if the proposed assignee is
    already a Lender hereunder, a Related Fund or a Wholly Owned Subsidiary of
    the same corporate parent of which the assigning Lender or any other Lender
    is a Subsidiary, or (b) otherwise with the consent of the Agent and, so long
    as no Event of Default exists, with the consent of the Company (which
    consent shall not be unreasonably withheld), in compliance with applicable
    laws in connection with such assignment, assign to one or more commercial
    banks, investment companies other financial institutions or mutual funds
    (each, an "Assignee") all or a portion of its interests, rights and
               --------
    obligations under

                                      -96-

 
    this Agreement and the other Credit Documents, including all or a portion,
    which need not be pro rata between the Revolving Loan, Incremental Revolving
    Loan, Incremental Term Loan and the Letter of Credit Exposure, of its
    Commitment, the portion of the Loan and Letter of Credit Exposure at the
    time owing to it and the Notes held by it, but excluding its rights and
    obligations as a Letter of Credit Issuer; provided, however, that:
                                              --------  -------

               (1)   the aggregate amount of the Commitment of the assigning
          Lender subject to each such assignment to any Assignee other than
          another Lender, a Related Fund or a Wholly Owned Subsidiary of the
          same corporate parent of which the assigning Lender or any other
          Lender is a Subsidiary (determined as of the date the Assignment and
          Acceptance with respect to such assignment is delivered to the Agent)
          shall be not less than $2,500,000 and in increments of $1,000,000 (or,
          if less, the entire remaining amount of the assigning Lender's
          Commitment); and

               (2)   the parties to each such assignment shall execute and
          deliver to the Agent an Assignment and Acceptance (the "Assignment and
                                                                  --------------
          Acceptance") substantially in the form of Exhibit 11.1.1, together
          ----------                                                        
          with the Note subject to such assignment and, except in the event of a
          transfer pursuant to Section 11.3, a processing and recordation fee of
          $3,000 payable to the Agent by the assigning Lender or the Assignee.

     Upon acceptance and recording pursuant to Section 11.1.4, from and after
     the effective date specified in each Assignment and Acceptance (which
     effective date shall be at least five Banking Days after the execution
     thereof unless waived by the Agent):

          (A)  the Assignee shall be a party hereto and, to the extent provided
               in such Assignment and Acceptance, have the rights and
               obligations of a Lender under this Agreement and

          (B)  the assigning Lender shall, to the extent provided in such
               assignment, be released from its obligations (but not its accrued
               liabilities) under this Agreement (and, in the case of an
               Assignment and Acceptance covering all or the remaining portion
               of an assigning Lender's rights and obligations under this
               Agreement, such Lender shall cease to be a party hereto but shall
               continue to be entitled to the benefits of Sections 3.2.4, 3.5
               and 9, as well as to any fees accrued for its account hereunder
               and not yet paid).

                                      -97-

 
          11.1.2. Terms of Assignment and Acceptance. By executing and
                  ---------------------------------- 
     delivering an Assignment and Acceptance, the assigning Lender and Assignee
     shall be deemed to confirm to and agree with each other and the other
     parties hereto as follows:

          (1)   other than the representation and warranty that it is the legal
     and beneficial owner of the interest being assigned thereby free and clear
     of any adverse claim, such assigning Lender makes no representation or
     warranty and assumes no responsibility with respect to any statements,
     warranties or representations made in or in connection with this Agreement
     or the execution, legality, validity, enforceability, genuineness,
     sufficiency or value of this Agreement, any other Credit Document or any
     other instrument or document furnished pursuant hereto;

          (2)   such assigning Lender makes no representation or warranty and
     assumes no responsibility with respect to the financial condition of the
     Company and its Subsidiaries or the performance or observance by the
     Company or any of its Subsidiaries of any of its obligations under this
     Agreement, any other Credit Document or any other instrument or document
     furnished pursuant hereto;

          (3)   such Assignee confirms that it has received a copy of this
     Agreement, together with copies of the most recent financial statements
     delivered pursuant to Section 7.2 or Section 6.4 and such other documents
     and information as it has deemed appropriate to make its own credit
     analysis and decision to enter into such Assignment and Acceptance;

          (4)   such Assignee will independently and without reliance upon the
     Agent, such assigning Lender or any other Lender, and based on such
     documents and information as it shall deem appropriate at the time,
     continue to make its own credit decisions in taking or not taking action
     under this Agreement;

          (5)   such Assignee appoints and authorizes the Agent to take such
     action as agent on its behalf and to exercise such powers under this
     Agreement as are delegated to the Agent by the terms hereof, together with
     such powers as are reasonably incidental thereto; and

          (6)   such Assignee agrees that it will perform in accordance with the
     terms of this Agreement all the obligations which are required to be
     performed by it as a Lender.

          11.1.3.   Register.  The Agent shall maintain at the Boston Office a
                    --------                                                  
     register (the "Register") for the recordation of (a) the names and
                    --------   
     addresses of the Lenders and the Assignees which assume rights and
     obligations pursuant to an assignment under Section 11.1.1, (b) the
     Percentage Interest of each such Lender as set forth in Exhibit 10.1 and
     (c) the amount of the Loan and Letter of Credit Exposure

                                      -98-

 
     owing to each Lender from time to time. The entries in the Register shall
     be conclusive, in the absence of manifest error, and the Company, the Agent
     and the Lenders may treat each Person whose name is registered therein for
     all purposes as a party to this Agreement. The Register shall be available
     for inspection by the Company or any Lender at any reasonable time and from
     time to time upon reasonable prior notice.

          11.1.4. Acceptance of Assignment and Assumption. Upon its receipt of a
                  ---------------------------------------
     completed Assignment and Acceptance executed by an assigning Lender and an
     Assignee (and any necessary consent of the Company) together with the Note
     subject to such assignment, and the processing and recordation fee referred
     to in Section 11.1.1, the Agent shall (a) accept such Assignment and
     Acceptance, (b) record the information contained therein in the Register
     and (c) give prompt notice thereof to the Company. Within five Banking Days
     after receipt of notice, the Company, at its own expense, shall execute and
     deliver to the Agent, in exchange for the surrendered Note, a new Note to
     the order of such Assignee in a principal amount equal to the applicable
     Commitment and Loan assumed by it pursuant to such Assignment and
     Acceptance and, if the assigning Lender has retained a Commitment and Loan,
     a new Note to the order of such assigning Lender in a principal amount
     equal to the applicable Commitment and Loan retained by it. Such new Note
     shall be in an aggregate principal amount equal to the aggregate principal
     amount of such surrendered Note, and shall be dated the date of the
     surrendered Note which it replaces.

          11.1.5. Federal Reserve Bank. Notwithstanding the foregoing provisions
                  -------------------- 
     of this Section 11, any Lender may at any time pledge or assign all or any
     portion of such Lender's rights under this Agreement and the other Credit
     Documents to a Federal Reserve Bank; provided, however, that no such pledge
                                          --------  -------
     or assignment shall release such Lender from such Lender's obligations
     hereunder or under any other Credit Document.

          11.1.6. Further Assurances. The Company and its Subsidiaries shall
                  ------------------
     sign such documents and take such other actions from time to time
     reasonably requested by an Assignee to enable it to share in the benefits
     of the rights created by the Credit Documents.

     11.2.  Credit Participants.  Each Lender may, without the consent of the
            -------------------                                              
Company or the Agent, in compliance with applicable laws in connection with such
participation, sell to one or more commercial banks, other financial
institutions or mutual funds (each a "Credit Participant") participations in all
                                      ------------------                        
or a portion of its interests, rights and obligations under this Agreement and
the other Credit Documents (including all or a portion of its Commitment, the
Loan and Letter of Credit Exposure owing to it and the Note held by it);
provided, however, that:
- --------  -------       

                                      -99-

 
          (1)   such Lender's obligations under this Agreement shall remain
     unchanged;

          (2)   such Lender shall remain solely responsible to the other parties
     hereto for the performance of such obligations;

          (3)   the Credit Participant shall be entitled to the benefit of the
     cost protection provisions contained in Sections 3.2.4, 3.5 and 9, but
     shall not be entitled to receive any greater payment thereunder than the
     selling Lender would have been entitled to receive with respect to the
     interest so sold if such interest had not been sold; and

          (4)   the Company, the Agent and the other Lenders shall continue to
     deal solely and directly with such Lender in connection with such Lender's
     rights and obligations under this Agreement, and such Lender shall retain
     the sole right as one of the Lenders to vote with respect to the
     enforcement of the obligations of the Obligors relating to the Loan and
     Letter of Credit Exposure and the approval of any amendment, modification
     or waiver of any provision of this Agreement (other than amendments,
     modifications, consents or waivers described in clause (b) of the proviso
     to Section 10.6).

Each Obligor agrees, to the fullest extent permitted by applicable law, that any
Credit Participant and any Lender purchasing a participation from another Lender
pursuant to Section 10.5 may exercise all rights of payment (including the right
of set-off), with respect to its participation as fully as if such Credit
Participant or such Lender were the direct creditor of the Obligors and a Lender
hereunder in the amount of such participation.

     11.3. Replacement of Lender. In the event that any Lender or, to the extent
           ---------------------
applicable, any Credit Participant (the "Affected Lender"):
                                         ---------------   

           (1)   fails to perform its obligations to fund any portion of the
     Loan or to issue any Letter of Credit on any Closing Date when required to
     do so by the terms of the Credit Documents, or fails to provide its portion
     of any Eurodollar Pricing Option pursuant to Section 3.2.1 or on account of
     a Legal Requirement as contemplated by Section 3.2.5;

           (2)   demands payment under the provisions of Section 3.5 in an
     amount materially in excess of the amounts with respect thereto demanded by
     the other Lenders;

           (3)   refuses to consent to a proposed extension of the Final
     Maturity Date that is consented to by all of the other Lenders; or

                                     -100-

 
           (4)   refuses to consent to a proposed amendment, modification,
     waiver or other action requiring consent of the holders of 100% of the
     Percentage Interests under Section 10.6(b) that is consented to by all of
     the other Lenders;

then, so long as no Event of Default exists, the Company shall have the right to
seek a replacement lender which is reasonably satisfactory to the Agent (the
"Replacement Lender"). The Replacement Lender shall purchase the interests of
- -------------------                                                          
the Affected Lender in the Loan, Letters of Credit and its Commitment and shall
assume the obligations of the Affected Lender hereunder and under the other
Credit Documents upon execution by the Replacement Lender of an Assignment and
Acceptance and the tender by it to the Affected Lender of a purchase price
agreed between it and the Affected Lender (or, if they are unable to agree, a
purchase price in the amount of the Affected Lender's Percentage Interest in the
Loan and Letter of Credit Exposure, or appropriate credit support for contingent
amounts included therein, and all other outstanding Credit Obligations then owed
to the Affected Lender).  No assignment fee pursuant to Section 11.1.1(ii) shall
be required in connection with such assignment.  Such assignment by any Affected
Lender who has performed its obligations under this Agreement shall be deemed an
early termination of any Eurodollar Pricing Option to the extent of the Affected
Lender's portion thereof, and the Company will pay to the Affected Lender any
resulting amounts due under Section 3.2.4.  Upon consummation of such
assignment, the Replacement Lender shall become party to this Agreement as a
signatory hereto and shall have all the rights and obligations of the Affected
Lender under this Agreement and the other Credit Documents with a Percentage
Interest equal to the Percentage Interest of the Affected Lender, the Affected
Lender shall be released from its obligations hereunder and under the other
Credit Documents, other than any obligations with respect to any claim that the
Company or any of its Subsidiaries may have against the Affected Lender arising
out of the failure of such Affected Lender to perform its obligations to fund
any portion of the Loan or to issue any Letter of Credit when required to do so
by the terms of the Credit Documents, and no further consent or action by any
party shall be required.  Upon the consummation of such assignment, the Company,
the Agent and the Affected Lender shall make appropriate arrangements so that a
new Note is issued to the Replacement Lender if it has acquired a portion of the
Loan.  The Company and the Guarantors shall sign such documents and take such
other actions reasonably requested by the Replacement Lender to enable it to
share in the benefits of the rights created by the Credit Documents.  Until the
consummation of an assignment in accordance with the foregoing provisions of
this Section 11.3, the Company shall continue to pay to the Affected Lender any
Credit Obligations as they become due and payable.

12.  CONFIDENTIALITY.  Each Lender will make no disclosure of confidential
     ---------------                                                      
information furnished to it by the Company or any of its Subsidiaries unless
such information shall have become public, except:

           (1)   in connection with operations under or the enforcement of this
     Agreement or any other Credit Document to Persons who have a reasonable
     need to be

                                     -101-

 
     furnished such confidential information and who agree to comply with the
     restrictions contained in this Section 12 with respect to such information;

           (2)   pursuant to any statutory or regulatory requirement or any
     mandatory court order, subpoena or other legal process;

           (3)   to any parent or corporate Affiliate of such Lender or to any
     Credit Participant, proposed Credit Participant or proposed Assignee;
     provided, however, that any such Person shall agree to comply with the
     --------  -------                                                     
     restrictions set forth in this Section 12 with respect to such information;

           (4)   to its independent counsel, auditors and other professional
     advisors with an instruction to such Person to keep such information
     confidential; and

           (5)   with the prior written consent of the Company, to any other
     Person.

13.  FOREIGN LENDERS.  If any Lender is not created or organized in, or under
     ---------------                                                         
the laws of, the United States of America or any state thereof, such Lender
shall deliver to the Company and the Agent the forms described in one of the
following two clauses:

            (1)   Two fully completed and duly executed United States Internal
     Revenue Service Forms 1001 or Forms 4224 or any successor form, as the case
     may be, certifying that such Lender is entitled to receive payments of the
     Credit Obligations payable to it without deduction or withholding of any
     United States federal income taxes; or

            (2)   A statement, executed by such Lender under penalty of perjury,
     certifying that such Lender is not a "bank" within the meaning of section
     881(c)(3)(A) of the Code and two fully completed and duly executed United
     States Internal Revenue Service Forms W-8 or any successor form, certifying
     that such Lender is not a "United States person" within the meaning of
     section 7701(a)(30) of the Code.
 
Each Lender that delivers any form or statement pursuant to this Section 13
further undertakes to renew such forms and statements by delivering to the
Company and the Agent any updated form, successor form or other certification,
as the case may be, on or before the date that any form or statement previously
delivered pursuant to this Section 13 expires or becomes obsolete or after the
occurrence of any event requiring a change in such most recent form or
statement. If at any time the Company and the Agent have not received all forms
and statements (including any renewals thereof) required to be provided by any
Lender pursuant to this Section 13, Section 3.5 shall not apply with respect to
any amount of  United States federal income taxes required to be withheld from
payments of the Credit Obligations to such Lender.

                                     -102-

 
14.  NOTICES.  Except as otherwise specified in this Agreement or any other
     -------                                                               
Credit Document, any notice required to be given pursuant to this Agreement or
any other Credit Document shall be given in writing.  Any notice, consent,
approval, demand or other communication in connection with this Agreement or any
other Credit Document shall be deemed to be given if given in writing (including
telex, telecopy or similar teletransmission) addressed as provided below (or to
the addressee at such other address as the addressee shall have specified by
notice actually received by the addressor), and if either (a) actually delivered
in fully legible form to such address (evidenced in the case of a telex by
receipt of the correct answer back) or (b) in the case of a letter, unless
actual receipt of the notice is required by any Credit Document five days shall
have elapsed after the same shall have been deposited in the United States
mails, with first-class postage prepaid and registered or certified.

     If to the Company or any of its Subsidiaries, to it at its address set
forth in Exhibit 7.1 (as supplemented pursuant to Sections 6.4.1 and 6.4.2), to
the attention of the chief financial officer.

     If to any Lender or the Agent, to it at its address set forth on the
signature pages of this Agreement or in the Register, with a copy to the Agent.

15. AMENDMENTS, CONSENTS, WAIVERS, ETC.
    ---------------------------------- 

     15.1. Lender Consents for Amendments. Except as otherwise set forth herein,
           ------------------------------ 
 the Agent may (and upon the written request of the Required Lenders the Agent
 shall) take or refrain from taking any action under this Agreement or any other
 Credit Document, including giving its written consent to any modification of or
 amendment to and waiving in writing compliance with any covenant or condition
 in this Agreement or any other Credit Document (other than an Interest Rate
 Protection Agreement) or any Default or Event of Default, all of which actions
 shall be binding upon all of the Lenders; provided, however, that:
                                           --------  -------       

          (1)   Except as provided below, without the written consent of the
     Lenders owning at least 60% of the Percentage Interests (disregarding the
     Percentage Interest of any Delinquent Lender during the existence of a
     Delinquency Period or of any Nonperforming Lender so long as such Lender is
     treated equally with the other Lenders with respect to any actions
     enumerated below), no written modification of, amendment to, consent with
     respect to, waiver of compliance with or waiver of a Default under, any of
     the Credit Documents (other than an Interest Rate Protection Agreement)
     shall be made.

          (2)   Without the written consent of such Lenders as own 100% of the
     Percentage Interests (disregarding the Percentage Interest of any
     Delinquent Lender during the existence of a Delinquency Period or of any
     Nonperforming Lender so long as such Lender is treated equally with the
     other Lenders with respect to any actions enumerated below):

                                     -103-

 
               (1)   None of the conditions specified in Section 5 shall be
          amended, waived or modified.

               (2)   No release of all or a material portion of the Credit
          Security or release of the Company or any Guarantor shall be made (in
          any event, without the written consent of the Lenders, the Agent may
          release particular items of Credit Security or particular Guarantors
          in dispositions permitted by Section 6.11, as modified by amendments
          thereto approved by the Required Lenders, and may release all Credit
          Security pursuant to Section 17 upon payment in full of the Credit
          Obligations and termination of the Commitments).

               (3)   No incurrence or existence of any Lien on all or
          substantially all of the Credit Security shall be permitted (other
          than Liens securing the Credit Obligations).

               (4)   No alteration shall be made of the Lenders' rights of set-
          off contained in Section 8.2.4.

               (5)    No amendment to or modification of this Section 15.1 or
          the definition of "Required Lenders" shall be made.

          (3)   Without the written consent of each Lender that is directly
     affected thereby, as well as such Lenders as own at least 60% of the
     Percentage Interests (disregarding the Percentage Interest of any
     Delinquent Lender during the existence of a Delinquency Period or of any
     Nonperforming Lender so long as such Lender is treated equally with the
     other Lenders with respect to any actions enumerated below):

               (1)   No reduction shall be made in (A) the amount of principal
          of the Loan owing to such Lender or reimbursement obligations for
          payments made under Letters of Credit payable or participated to such
          Lender, (B) the interest rate on the portion of the Loan owing to such
          Lender or (C) the Letter of Credit fees or commitment fees owing to
          such Lender with respect to the credit facility provided herein (other
          than amendments and waivers approved by the Required Lenders that
          modify defined terms used in calculating the Applicable Margin or
          Consolidated Excess Cash Flow or that waive an increase in the
          Applicable Rate as a result of an Event of Default).

               (2)   No change shall be made in the stated, scheduled time of
          payment of any portion of the Loan owing to such Lender or interest
          thereon or reimbursement of payments made under Letters of Credit or
          fees relating to any of the foregoing payable to such Lender and no
          waiver shall be made of any

                                     -104-

 
          Default under Section 8.1.1 with respect to such Lender (other than
          amendments and waivers approved by the Required Lenders that modify
          defined terms used in calculating the Applicable Margin or
          Consolidated Excess Cash Flow).

               (3)   No increase shall be made in the amount, or extension of
          the term, of the stated Commitments of such Lender beyond that
          provided for under Section 2.

          (4)   Without the written consent of such Lenders owning at least 60%
     of the Percentage Interests in a particular Tranche (disregarding the
     Percentage Interest of any Delinquent Lender during the existence of a
     Delinquency Period or of any Nonperforming Lender so long as such Lender is
     treated equally with the other Lenders with respect to any actions
     enumerated below) voting as a separate class, no change may be made in the
     allocation of mandatory prepayments under Section 4.3 between the
     respective Tranches.

          (5)   Without the written consent of the Agent, no amendment or
     modification of any Credit Document shall affect the rights or duties of
     the Agent under the Credit Documents.

          (6)   Without the written consent of a Letter of Credit Issuer, no
     amendment or modification of any Credit Document shall affect the rights or
     duties of such Letter of Credit Issuer under the Credit Documents.

     15.2.  Course of Dealing; No Implied Waivers.  No course of dealing between
            -------------------------------------                               
any Lender or the Agent, on one hand, and the Company or any other Obligor, on
the other hand, shall operate as a waiver of any of the Lenders', the Agent's,
the Company's or any other Obligor's rights under this Agreement or any other
Credit Document or with respect to the Credit Obligations.  In particular, no
delay or omission on the part of any Lender, the Agent, the Company or any other
Obligor in exercising any right under this Agreement or any other Credit
Document or with respect to the Credit Obligations shall operate as a waiver of
such right or any other right hereunder or thereunder.  A waiver on any one
occasion shall not be construed as a bar to or waiver of any right or remedy on
any future occasion.  No waiver, consent or amendment with respect to this
Agreement or any other Credit Document shall be binding unless it is in writing
and signed by the Agent or the Required Lenders.

16.  NO STRICT CONSTRUCTION.  The parties have participated jointly in the
     ----------------------                                               
negotiation and drafting of this Agreement and the other Credit Documents with
counsel sophisticated in financing transactions.  In the event an ambiguity or
question of intent or interpretation arises, this Agreement and the other Credit
Documents shall be construed as if drafted jointly by the parties and no
presumption or burden of proof shall arise favoring or 
                                                                                

                                     -105-

 
disfavoring any party by virtue of the authorship of any provisions of this
Agreement and the other Credit Documents.

17.  DEFEASANCE.  When all Credit Obligations have been paid, performed and
     ----------                                                            
reasonably determined by the Lenders to have been indefeasibly discharged in
full, and if at the time no Lender continues to be committed to extend any
credit to the Company hereunder or under any other Credit Document, this
Agreement and the other Credit Documents shall terminate and, at the Company's
written request, accompanied by such certificates and other items as the Agent
shall reasonably deem necessary, the Credit Security shall revert to the
Obligors and the right, title and interest of the Lenders therein shall
terminate.  Thereupon, on the Obligors' demand and at their cost and expense,
the Agent shall execute proper instruments, acknowledging satisfaction of and
discharging this Agreement and the other Credit Documents, and shall redeliver
to the Obligors any Credit Security then in its possession; provided, however,
                                                            --------  ------- 
that Sections 3.2.4, 3.5, 9, 10.7.7, 10.10, 12, 18 and 19 shall survive the
termination of this Agreement.

 18. VENUE; SERVICE OF PROCESS.  Each of the Company and the other Obligors:
     -------------------------                                              

          (1)   Irrevocably submits to the nonexclusive jurisdiction of the
     state courts of The Commonwealth of Massachusetts and to the nonexclusive
     jurisdiction of the United States District Court for the District of
     Massachusetts for the purpose of any suit, action or other proceeding
     arising out of or based upon this Agreement or any other Credit Document or
     the subject matter hereof or thereof.

          (2)   Waives to the extent not prohibited by applicable law that
     cannot be waived, and agrees not to assert, by way of motion, as a defense
     or otherwise, in any such proceeding brought in any of the above-named
     courts, any claim that it is not subject personally to the jurisdiction of
     such court, that its property is exempt or immune from attachment or
     execution, that such proceeding is brought in an inconvenient forum, that
     the venue of such proceeding is improper, or that this Agreement or any
     other Credit Document, or the subject matter hereof or thereof, may not be
     enforced in or by such court.

          (3)   Consents to service of process in any such proceeding in any
     manner at the time permitted by Chapter 223A of the General Laws of The
     Commonwealth of Massachusetts and agrees that service of process by
     registered or certified mail, return receipt requested, at its address
     specified in or pursuant to Section 14 and addressed to the attention of
     its general counsel is reasonably calculated to give actual notice.

19.  WAIVER OF JURY TRIAL.  TO THE EXTENT NOT PROHIBITED BY APPLICABLE LAW
     --------------------                                                 
THAT CANNOT BE WAIVED, EACH OF THE COMPANY, THE OTHER OBLIGORS, THE AGENT AND
THE LENDERS WAIVES, AND COVENANTS 

                                     -106-

 
THAT IT WILL NOT ASSERT (WHETHER AS PLAINTIFF, DEFENDANT OR OTHERWISE), ANY
RIGHT TO TRIAL BY JURY IN ANY FORUM IN RESPECT OF ANY ISSUE, CLAIM OR PROCEEDING
ARISING OUT OF THIS AGREEMENT OR ANY OTHER CREDIT DOCUMENT OR THE SUBJECT MATTER
HEREOF OR THEREOF OR ANY CREDIT OBLIGATION OR IN ANY WAY CONNECTED WITH THE
DEALINGS OF THE LENDERS, THE AGENT, THE COMPANY OR ANY OTHER OBLIGOR IN
CONNECTION WITH ANY OF THE ABOVE, IN EACH CASE WHETHER NOW EXISTING OR HEREAFTER
ARISING AND WHETHER IN CONTRACT, TORT OR OTHERWISE. Each of the Company and the
other Obligors acknowledges that it has been informed by the Agent that the
provisions of this Section 19 constitute a material inducement upon which each
of the Lenders has relied and will rely in entering into this Agreement and any
other Credit Document, and that it has reviewed the provisions of this Section
19 with its counsel. Each of the Lenders acknowledges that it has been informed
by the Company that the provisions of this Section 19 constitute a material
inducement upon which the Company and each of the other Obligors have relied and
will rely in entering into this Agreement and any other Credit Document, and
that it has reviewed the provisions of this Section 19 with its counsel. Any
Lender, the Agent, the Company or any other Obligor may file an original
counterpart or a copy of this Section 19 with any court as written evidence of
the consent of the Company, the other Obligors, the Agent and the Lenders to the
waiver of their rights to trial by jury.

20.  GENERAL.  Time is (and shall be) of the essence in this Agreement and the
     -------                                                                  
other Credit Documents.  All covenants, agreements, representations and
warranties made in this Agreement or any other Credit Document or in
certificates delivered pursuant hereto or thereto shall be deemed to have been
relied on by each Lender, notwithstanding any investigation made by any Lender
on its behalf, and shall survive the execution and delivery to the Lenders
hereof and thereof.  The invalidity or unenforceability of any provision hereof
shall not affect the validity or enforceability of any other provision hereof,
and any invalid or unenforceable provision shall be modified so as to be
enforced to the maximum extent of its validity or enforceability. The headings
in this Agreement are for convenience of reference only and shall not limit or
otherwise affect the meaning hereof.  This Agreement and the other Credit
Documents constitute the entire understanding of the parties with respect to the
subject matter hereof and thereof and supersede all prior and contemporaneous
understandings and agreements, whether written or oral.  This Agreement may be
executed in any number of counterparts which together shall constitute one
instrument.  This Agreement shall be governed by and construed in accordance
with the laws (other than the conflict of laws rules) of The Commonwealth of
Massachusetts.



              [THE REMAINDER OF THIS PAGE IS INTENTIONALLY BLANK]

                                     -107-

 
     Each of the undersigned has caused this Agreement to be executed and
delivered by its duly authorized officer as an agreement under seal as of the
date first above written.


                                  SBA TELECOMMUNICATIONS, INC.


                                  By /s/ Jeffrey A. Stoops
                                    --------------------------------------------
                                    Title: Senior Vice President--Corporate
                                           Development

                                  COMMUNICATION SITE SERVICES, INC.
                                  SBA COMMUNICATIONS INTERNATIONAL, INC.
                                  SBA, INC.
                                  SBA LEASING, INC.
                                  SBA SUBSIDIARY HOLDINGS, INC.
                                  SBA TOWERS, INC.
  
 
                                  By /s/ Jeffrey A. Stoops
                                    --------------------------------------------
                                    As Senior Vice President or Vice President
                                    of each of the foregoing corporations
 

                                  SBA COMMUNICATIONS CORPORATION


                                  By /s/ Jeffrey A. Stoops
                                    --------------------------------------------
                                    Title: Senior Vice President--Corporate
                                           Development

                                  BANKBOSTON, N.A.

                                  By /s/ Donna Fraser
                                    --------------------------------------------
                                    Title:

                                  BANKBOSTON, N.A.
                                  Media & Communications Division
                                  100 Federal Street
                                  Boston, Massachusetts 02110
                                  Telecopy: (617) 434-3401

 
                         Telex:  940581

                         FIRST UNION NATIONAL BANK


                         By /s/ Bruce W. Loftin
                           ----------------------------------------
                            Title:

                         FIRST UNION NATIONAL BANK 
                         One First Union Center
                         Charlotte, North Carolina  28288-0735


                         FLEET NATIONAL BANK


                         By /s/ Jeffrey J. McLaughlin
                           ----------------------------------------
                            Title:

                         FLEET NATIONAL BANK
                         One Federal Street
                         MA of D 03D
                         Boston, Massachusetts  02109



                         LEHMAN COMMERCIAL PAPER INC.


                         By /s/ Michele Swanson
                           ----------------------------------------
                            Title:


                         LEHMAN COMMERCIAL PAPER INC.
                         3 World Financial Center, 9th Floor
                         New York, New York  10285