EXHIBIT 10.14 

                        SBA COMMUNICATIONS CORPORATION
                            SUBORDINATION AGREEMENT



     This Agreement, dated as of August 8, 1997, is among SBA Communications
Corporation, a Florida corporation (the "Company"), the undersigned holders of
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in excess of 73% of the Company's 4% Series A Convertible Preferred Stock, $0.01
par value per share, and BankBoston, N.A., as agent (the "Agent") for itself and
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the other Lenders under the Credit Agreement (as defined below).  The parties
agree as follows:

1.  Reference to Credit Agreement; Certain Rules of Construction; Definitions.
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Reference is made to the Credit Agreement dated as of the date hereof, as from
time to time in effect (the "Credit Agreement"), among the Company, its
                             ----------------                          
Subsidiaries from time to time party thereto, the Lenders and the Agent.  Except
as the context otherwise explicitly requires, (a) the capitalized term "Section"
refers to sections of this Agreement, (b) references to a particular Section
shall include all subsections thereof and (c) the word "including" shall be
construed as "including without limitation".  Capitalized terms defined in the
Credit Agreement and not otherwise defined herein are used herein with the
meanings so defined.  Certain other capitalized terms are used in this Agreement
as specifically defined in this Section 1 as follows:

     1.1. "Junior Creditor" means each holder of any Preferred Stock and each
           ---------------                                                   
other Person becoming a party to this Agreement (or a substantially similar
subordination agreement) pursuant to Section 8.1.

     1.2. "Preferred Stock" means, collectively, the Series A Preferred Stock,
           ---------------                                                    
Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock.

     1.3. "Reorganization" means any voluntary or involuntary dissolution,
           --------------                                                 
winding-up, liquidation, reorganization by judicial proceedings, bankruptcy,
insolvency, receivership or other statutory or common law proceedings, including
any proceeding under the federal Bankruptcy Code or any similar law of any other
jurisdiction, involving the Company, any of its properties or the readjustment
of the liabilities of the Company or any assignment for the benefit of creditors
or any marshaling of the assets or liabilities of the Company.

     1.4. "Senior Indebtedness" means all Credit Obligations and all renewals,
           -------------------                                                
extensions and refinancings of the Credit Obligations.

     1.5. "Signatory Holders" means the undersigned holders of at least 73% of
           -----------------
the outstanding Preferred Stock and each other Person to whom Subordinated
Indebtedness is transferred by such a Signatory Holder in a transaction
complying with Section 8.1.

     1.6. "Subordinated Indebtedness" means:
           -------------------------        

 
          (a) Rights to receive dividends on and redemptions of any Preferred
     Stock and all other Indebtedness of the Company and its Subsidiaries to the
     Junior Creditors with respect to the Preferred Stock; and

          (b)  All other obligations of the Company and its Subsidiaries to the
     Junior Creditors with respect to the items in clause (a), whether now
     existing or hereafter arising, including any claim against the Company and
     its Subsidiaries in respect of rescission, indemnification, expenses,
     damages or otherwise.

2.  Subordination Covenants.  Each of the Company and each Junior Creditor
    -----------------------                                               
covenants that, so long as any part of the Senior Indebtedness is outstanding
and until the Lenders' obligations to extend credit under each Credit Document
shall have been terminated, each of them will comply with the following
provisions:

     2.1. Subordination.  To the extent and in the manner provided in this
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Agreement, the payment of any Subordinated Indebtedness is and shall be
expressly subordinated and junior in right of payment to the prior payment in
full of all Senior Indebtedness, and the Subordinated Indebtedness is
subordinated as a claim against the Company, any of its Subsidiaries, any
guarantor of the Senior Indebtedness or any of their respective assets to the
prior payment in full of the Senior Indebtedness, in each case whether such
claim is (a) in the ordinary course of business or (b) in the event of any
Reorganization.

     2.2. Restricted Payments.  The Company and its Subsidiaries will not make,
          -------------------                                                  
and the Junior Creditors will not accept or receive, any payment of any
Subordinated Indebtedness, whether in cash, securities or other property or by
way of conversion, exchange or set-off or otherwise, and no such payment shall
become due; provided, however, that the Company may make, and the Junior
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Creditors may accept and receive, payments as follows:

          2.2.1. 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 redeem outstanding shares of
     Preferred Stock after the fifth anniversary of the date of the initial
     closing of the private placement of Series A Preferred Stock pursuant to
     the Offering Memorandum; provided, however, that during any single fiscal
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     year (a) any such redemption by the Company shall occur after the date upon
     which the Company makes any prepayment to the Lenders pursuant to section
     4.3.2 (Excess Cash Flow) of the Credit Agreement; and (b) all such
     redemptions made during such fiscal year shall be in an aggregate amount no
     greater than the amount of any prepayment pursuant to such section 4.3.2
     made to the Lenders in such fiscal years; and provided, further, that the
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     number of shares redeemed pursuant to this Section 2.2.1 during any fiscal
     year shall not exceed 25% of the shares outstanding on March 31, 2002.

                                      -2-

 
          2.2.2. So long as immediately before and after giving effect thereto
     no Default exists, the Company may redeem outstanding shares of Preferred
     Stock after December 31, 1999 from the proceeds of a public offering of the
     Company's Common Stock raising gross proceeds of at least $20,000,000.

     2.3. Reorganization.  In the event of any Reorganization, all Senior
          --------------                                                 
Indebtedness shall first be paid in full before any payment is made on account
of any Subordinated Indebtedness. In any proceedings seeking to effect a
Reorganization any payment or distribution of any kind or character, whether in
cash or property or securities, which may be payable or deliverable in respect
of any such Subordinated Indebtedness shall be paid or delivered directly to the
Agent for application to payment of the Senior Indebtedness, unless and until
all Senior Indebtedness shall have been paid in full.

     2.4. Specific Powers in Reorganization.  In any proceedings with respect to
          ---------------------------------                                     
any Reorganization, the Junior Creditors irrevocably authorize the Agent:

          (a)  In the event the Subordinated Indebtedness claims have not been
     properly submitted and presented in such proceedings by the 10th day prior
     to the expiration date for the submission and presentment of claims, to
     prove and enforce any claims on the Subordinated Indebtedness owed by the
     Company and its Subsidiaries to the Junior Creditors either in the name of
     the Agent or in the names of the Junior Creditors as the attorney-in-fact
     of the Junior Creditors for such limited purpose;

          (b)  To accept and execute receipts for any payment or distribution
     made with respect to any such Subordinated Indebtedness and to apply such
     payment or distribution to the payment of the Senior Indebtedness; and

          (c)  To take any lawful action necessary to effectuate the foregoing,
     either in the name of the Agent or in the name of the Junior Creditors as
     the attorney-in-fact of the Junior Creditors for such limited purpose.

     2.5. Turnover of Payments.  If any payment or distribution of the assets of
          --------------------                                                  
the Company or any of its present or future Subsidiaries of any kind or
character (other than payments permitted by Section 2.2) shall be received, by
way of set-off or otherwise, by the Signatory Holders in contravention of
Section 2.2 or 2.3 and, in the case of any contravention of Section 2.2 on
account of a Default existing before or after giving effect to such payment or
distribution, the Company or the Agent shall have given the Signatory Holders
written notice of such Default prior to the receipt by the Signatory Holders of
such payment, then such payment or distribution shall be promptly paid over to
the Agent (who shall have the right to convert any such assets into cash) for
application to the payment of all Senior Indebtedness remaining unpaid, after
giving effect to any concurrent payment or distribution to the holders of Senior
Indebtedness.  Any funds or property remaining after all such Senior
Indebtedness has been paid in full at a time when the Lenders' obligations to
extend credit under the Credit 

                                      -3-

 
Documents have been terminated shall be promptly remitted by the Agent to the
Signatory Holders. Upon written request by the Signatory Holders, the Agent
shall provide the Signatory Holders with computations showing any payments or
assets of the Company received by the Agent pursuant to this Section 2.5, any
conversion of any such assets into cash and the application of such payments on
account of the Senior Indebtedness.

     2.6. Restrictions on Acceleration.  Notwithstanding any contrary provision
          ----------------------------                                         
of any Subordinated Indebtedness or of any agreement or instrument relating
thereto, (a) no Subordinated Indebtedness (other than payments permitted by
Section 2.2) shall become or be declared to be due and payable prior to the date
on which the Senior Indebtedness becomes or is declared to be due and payable
and (b) if any Senior Indebtedness shall have become or been declared to be due
and payable prior to its stated maturity, the Subordinated Indebtedness shall
become immediately due and payable.

     2.7. Restrictions on Remedies.  The Junior Creditors shall not, without the
          ------------------------                                              
Agent's prior written consent, institute proceedings to enforce any Subordinated
Indebtedness, notwithstanding any provision to the contrary contained in any
Subordinated Indebtedness or in any agreement or instrument relating thereto.
Without limiting the generality of the foregoing sentence, the Junior Creditors
shall not, without the Agent's prior written consent, commence or join with any
other creditor of the Company and its Subsidiaries in commencing any proceeding
against the Company and its Subsidiaries seeking to effect a Reorganization.
Notwithstanding the foregoing, in the event of any Reorganization, the Junior
Creditors shall be entitled to prove and enforce their claims on the
Subordinated Indebtedness in their own names subject, however, to the
subordination and application provisions contained herein.

     2.8. No Collateral.  The Company and its Subsidiaries shall not grant, and
          -------------                                                        
the Junior Creditors shall not demand, accept or receive, any collateral, direct
or indirect, for any Subordinated Indebtedness.

     2.9. No Other Subordination.  Each Junior Creditor represents that the
          ----------------------                                           
Subordinated Indebtedness has not been subordinated by agreement of such Junior
Creditor to any obligations other than the Senior Indebtedness and covenants
that it will not subordinate the Subordinated Indebtedness to any other
obligations except with the prior written consent of the Agent.

     2.10. Payment in Full.  For the purposes of this Agreement, no Senior
           ---------------                                                
Indebtedness shall be deemed to have been paid in full unless the holder thereof
shall have received cash equal to the amount thereof then outstanding; provided,
                                                                       -------- 
however, that if the Lenders are required by reason of a judgment or order of
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any court or administrative authority having competent jurisdiction to repay any
amounts or property received by the Lenders on account of the Credit Obligations
and the Lenders repay or return such amounts or property, then the subordination
provisions of this Agreement shall be reinstated retroactively with respect to
the amounts so repaid or property so returned as if such amounts or property had
never been 

                                      -4-

 
received by the Lenders, notwithstanding any termination thereof or the
cancellation of any instrument or agreement evidencing any of the Credit
Obligations.

3.  Effect of Provisions; Subrogation.
    --------------------------------- 

     3.1. Effect of Provisions; Relative Rights.  The provisions hereof as to
          -------------------------------------                              
subordination are solely for the purpose of defining the relative rights of the
holders of Senior Indebtedness on one hand and the Junior Creditors on the other
hand, and such provisions shall not impair as between the Company and the Junior
Creditors the obligation of the Company to pay to the Junior Creditors any
Subordinated Indebtedness owed by the Company to the Junior Creditors and all
other amounts in respect thereof, nor shall any such provisions prevent the
Junior Creditors from exercising all remedies otherwise permitted by applicable
law or under the terms of such Subordinated Indebtedness upon a default
thereunder, except to the extent prohibited by this Agreement.

     3.2. Subrogation.  When all Senior Indebtedness has been paid in full and
          -----------                                                         
the Lenders' obligations to extend credit under all Credit Documents have been
terminated, the Junior Creditors shall be subrogated to the rights of the
holders of Senior Indebtedness to receive payments or distributions of assets of
the Company or any of its Subsidiaries that would be deemed payable on the
Senior Indebtedness until the Subordinated Indebtedness shall be paid in full.
For the purposes of such subrogation, no payments or distributions to the
holders of Senior Indebtedness of any cash, property or securities to which the
Junior Creditors would be entitled except for the provisions of this Agreement,
and no payment over pursuant to the provisions of this Agreement to the holders
of Senior Indebtedness by the Junior Creditors, shall, as between the Company or
any of its Subsidiaries and their creditors other than the holders of Senior
Indebtedness, on one hand, and the Junior Creditors, on the other hand, be
deemed to be a payment by the Company or any of its Subsidiaries to or on
account of Senior Indebtedness.

4.  Further Assurances.  Each of the Company and each Junior Creditor covenants
    ------------------                                                         
to execute and deliver to the Agent such further instruments and to take such
further action as the Agent may at any time or times reasonably request in order
to carry out the provisions and intent of this Agreement.

5.  Representations and Warranties.
    ------------------------------ 

     5.1. Signatory Holders.  Each Signatory Holder represents and warrants as
          -----------------                                                   
to itself only (and not as to any other Junior Creditor) as follows:

          5.1.1. Existence and Power.  Such Signatory Holder is a validly
                 ------------------- 
     existing entity with all power and authority necessary to enter into and
     perform this Agreement.

                                      -5-

 
          5.1.2. Authorization and Enforceability.  Such Signatory Holder has
                 --------------------------------                            
     taken all action required to execute, deliver and perform this Agreement.
     This Agreement constitutes the legal, valid and binding obligation of such
     Signatory Holder, enforceable against such Signatory Holder in accordance
     with its terms.

          5.1.3. No Legal Obstacle to Agreements.   Neither the execution and
                 -------------------------------                             
     delivery of this Agreement, nor the consummation of any transaction
     referred to in or contemplated by this Agreement, nor the fulfillment of
     the terms hereof, has constituted or resulted, or will constitute or
     result, in:

          (a)  Any breach or termination of the provisions of any agreement,
     instrument, deed or lease to which such Signatory Holder is a party or by
     which it is bound, or of the organizational and governing documents of such
     Signatory Holder; or

          (b)  To the best of such Signatory Holder's knowledge, the violation
     of any law, statute, judgment, decree or governmental order, rule or
     regulation applicable to such Signatory Holder.

     No approval, authorization or other action by, or declaration to or filing
     with, any governmental or administrative authority or any other Person is
     required to be obtained or made by such Signatory Holder in connection with
     the execution, delivery and performance of this Agreement or any other
     Credit Document to which it is party or the transactions contemplated
     hereby or thereby.

          5.1.4. 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 to which such Signatory Holder is a
     party or, to the knowledge of such Signatory Holder, is any such litigation
     or proceeding threatened, which seeks to enjoin the consummation, or which
     questions the validity, of any of the transactions contemplated by this
     Agreement.

     5.2.  Company.  The Company represents and warrants as follows:
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          5.2.1.  Outstanding Preferred Stock.  As of the date hereof Series A
                  ---------------------------                                 
     Preferred Stock is the only Preferred Stock outstanding.  Shares of Series
     B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock
     are issuable only in connection with, and to holders of,  Series A
     Preferred Stock or other shares of Preferred Stock issued directly or
     indirectly in connection with, and to holders of, Series A Preferred Stock.

          5.2.2.  Authority of Signatory Holders. The Signatory Holders
                  ------------------------------
     constitute the holders of at least 73% of the outstanding Preferred Stock
     and have the authority to bind all other Junior Creditors to this Agreement
     by virtue of Article E of the Amended

                                      -6-

 
     and Restated Certificate of Designation, Preferences, Rights and
     Limitations Amending Terms of the Preferred Stock dated April 1977.

6.  Information Regarding the Company.  Each Junior Creditor agrees that it has
    ---------------------------------                                          
made such investigation as it deems desirable of the risks undertaken by it in
entering into this Agreement and is fully satisfied that it understands all such
risks.  Each Junior Creditor waives any obligation which may now or hereafter
exist on the part of the Agent or any holder of any Senior Indebtedness to
inform such Junior Creditor of the risks being undertaken by entering into this
Agreement or of any changes in such risks and such Junior Creditor undertakes to
keep itself informed of such risks and any changes therein.  Each Junior
Creditor expressly waives (except to the extent prohibited by applicable law
which cannot be waived) any duty which may now or hereafter exist on the part of
the Agent or any holder of any Senior Indebtedness to disclose to such Junior
Creditor any matter related to the business, operations, character, collateral,
credit, condition (financial or otherwise), income or prospects of the Company
or its Affiliates, properties or management, whether now or hereafter known by
any Lender.  Each Junior Creditor agrees that it assumes sole responsibility for
obtaining from the Company and its Affiliates all information concerning the
Credit Agreement and all other Credit Documents and all other information as to
the Company and its Subsidiaries and their respective Affiliates, properties or
management or anything relating to any of the above as it deems necessary or
desirable.


7.  Continuing Agreement; Lender Powers; etc.
    -----------------------------------------

     7.1. Continuing Agreement, etc.  This Agreement shall be a continuing
          -------------------------                                      
agreement and shall remain in full force and effect until the payment in full of
the Senior Indebtedness and the termination of the Lenders' obligations to
extend credit under all Credit Documents.

     7.2. Consent to Credit Agreement.  Each Junior Creditor acknowledges
          ---------------------------                                    
receipt from the Company of a correct and complete copy of the Credit Agreement
as in effect as of the date hereof, and consents to all of the provisions of the
Credit Agreement as in effect as of such date.

     7.3. Power to Modify Credit Agreement, etc.  To the extent permitted by
          -------------------------------------                             
applicable law that cannot be waived, each Junior Creditor grants the Agent and
the Lenders full power, in their sole discretion, without notice to or consent
by such Junior Creditor and without in any way affecting the subordination of
the Subordinated Indebtedness provided in this Agreement, but subject to the
proviso set forth at the end of this Section 7.3:

          7.3.1.  To waive compliance with any Default under, and to consent to
     any amendment or change of any terms of, the Credit Agreement, any other
     Credit Document, the Credit Security, the Credit Obligations or any
     Guarantee thereof (each as from time to time in effect);

                                      -7-

 
          7.3.2. To grant one or more extensions or renewals of the Credit
     Obligations (for any duration), and any other indulgence with respect
     thereto and to effect any total or partial release (by operation of law or
     otherwise), discharge, compromise or settlement with respect to the
     obligations of the Company in respect of the Credit Obligations, whether or
     not rights against the Company under this Agreement are reserved in
     connection therewith;

          7.3.3. To take security in any form for the Credit Obligations and to
     consent to the addition to or the substitution, exchange, release, failure
     to perfect or any other disposition of, and to deal in any other manner
     with, any property which may from time to time secure the Credit
     Obligations whether or not the property, if any, received upon the exercise
     of such power shall be of a character or value the same as or different
     from the character or value of any property disposed of, and to obtain,
     modify or release any present or future Guarantees of the Credit
     Obligations and to proceed against any of the Credit Security or such
     Guarantees in any order;

          7.3.4. To extend credit under the Credit Agreement or any other Credit
     Document, or otherwise, in such amount as the Lenders may determine,
     whether for a greater or lesser amount than is presently in effect, even
     though the financial condition of the Company and its Subsidiaries may have
     deteriorated since the date hereof; and

          7.3.5. To collect or liquidate or realize upon any of the Credit
     Obligations or the Credit Security in any lawful manner or to refrain from
     collecting or liquidating or realizing upon any of the Credit Obligations
     or the Credit Security;

     provided, however, that the Company and the Agent agree not to amend the
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     definition of "Consolidated Excess Cash Flow" or of the terms included in
     such definition without the consent of the holders of at least 66-2/3% of
     the outstanding Preferred Stock if the effect of such amendment would be to
     reduce the amount of Consolidated Excess Cash Flow.

     7.4. No Impairment by Company, Lenders, etc.  No right of the Lenders or
          --------------------------------------                             
any present or future holder of any Senior Indebtedness shall at any time be
prejudiced or impaired by any act or failure to act on the part of the Company,
including any noncompliance by the Company with the terms of this Agreement, or
by any lawful act or failure to act, in good faith, by any Lender or any such
holder (other than amendments to the Credit Documents entered into by the Agent
or the Lenders).

     7.5. Specific Performance.  The Agent is authorized to demand specific
          --------------------                                             
performance of this Agreement at any time when the Company or any Junior
Creditor shall have failed to comply with any provision hereof applicable to it,
and each of them irrevocably waives any 

                                      -8-

 
defense based on the adequacy of a remedy at law which might be asserted as a
bar to the remedy of specific performance hereof in any action brought therefor
by the Lenders.

8.   Transfers; Successors and Assigns.
     --------------------------------- 

     8.1. Transfers.  No Signatory Holder will sell, assign, transfer or
          ---------                                                     
otherwise dispose of any Subordinated Indebtedness except to another Person
which shall have entered into this Agreement expressly as a Signatory Holder.
The other Junior Creditors will not sell, assign, transfer or otherwise dispose
of any Subordinated Indebtedness except to another Person which shall have
entered into this Agreement or another agreement with the Agent, in a form
satisfactory to the Agent, providing for subordination of such Subordinated
Indebtedness to the prior payment of the Credit Obligations on the terms
provided in this Agreement.

     8.2. Successors and Assigns.  The provisions of this Agreement shall inure
          ----------------------                                               
to the benefit of the Lenders and their successors and assigns and shall be
binding upon each of the Company and the Junior Creditors and their respective
successors and assigns.  The Company and the Junior Creditors may not assign
their rights or obligations under this Agreement except to the extent provided
in Section 8.1.

9.   Notices.  Any notice or other communication in connection with this
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Agreement 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 answerback) or (b) in the case of a letter, five business 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, to it at its address specified in or pursuant to Section
16 of the Credit Agreement, to the attention of its chief financial officer.

     If to any Signatory Holder, to it at its address set forth below its
signature hereto.

     If to any other Junior Creditor, to it in care of the Company.

     If to the Agent, to it at its address specified in or pursuant to Section
16 of the Credit Agreement.

10.  Venue; Service of Process.  Each of the Company and each Junior Creditor:
     -------------------------                                                

          (a)  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, 

                                      -9-

 
     action or other proceeding arising out of or based upon this Agreement or
     any other Credit Document or the subject matter hereof or th e reof; and

          (b)  Waives to the extent not prohibited by applicable law, 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 any 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.

Each of the Company and each Junior Creditor consents to service of process in
any such proceeding in any manner 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 9 is reasonably calculated to give actual notice.

11.  WAIVER OF JURY TRIAL.  TO THE EXTENT NOT PROHIBITED BY APPLICABLE LAW WHICH
     --------------------                                                       
CANNOT BE WAIVED, EACH OF THE AGENT, THE COMPANY AND EACH JUNIOR CREDITOR
WAIVES, AND COVENANTS 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, DEMAND OR ACTION ARISING OUT OF OR BASED UPON THIS AGREEMENT, THE CREDIT
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 AGENT,
THE COMPANY OR THE JUNIOR CREDITORS IN CONNECTION WITH ANY OF THE ABOVE, IN EACH
CASE WHETHER NOW EXISTING OR HEREAFTER ARISING AND WHETHER IN CONTRACT OR TORT
OR OTHERWISE.  Each of the Company and each Signatory Holder acknowledges that
it has been informed by the Agent that the provisions of this Section 11
constitute a material inducement upon which each of the Lenders has relied, is
relying and will rely in entering into the Credit Agreement and any other Credit
Document, and that it has reviewed the provisions of this Section 11 with its
counsel.  The Agent, the Company or any Junior Creditor may file an original
counterpart or a copy of this Section 11 with any court as written evidence of
the consent of the Agent, the Company and such Junior Creditor to the waiver of
the right to trial by jury.

12.  General.  All covenants, agreements, representations and warranties made in
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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 the Agent 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 

                                      -10-

 
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, alter 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 current understandings and agreements,
whether written or oral. This Agreement is a Credit Document and 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.

                                      -11-

 
     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
dated first written above.

                         SBA COMMUNICATIONS CORPORATION


                         By /S/ Jeffrey A. Stoops
                           ________________________________
                           Title: Senior Vice President



                         BANKBOSTON, N.A.,
                           as Agent under the Credit Agreement


                         By /s/ Reginald T. Dawson
                           ________________________________
                           Title: Director


                         ABS CAPITAL PARTNERS II, L.P.

                         By:  ABS PARTNERS II, LLC, its General Partner


                              By: /s/ Donald B. Hebb, Jr.
                                 __________________________
                                 Donald B. Hebb, Jr., Managing Member

                         ABS MB MANAGEMENT
                         135 East Baltimore Street
                         Baltimore, MD  21202
                         Telecopy:  (410) 895-4380

                         ADVENT ATLANTIC AND PACIFIC III, L.P.

                         By:  TA ASSOCIATES AAP III PARTNERS, L.P., its
                              General Partner

                              By:   TA ASSOCIATES, INC., its
                                    General Partner

                                    By: /s/ Brian J. Conway
                                       ____________________
                                       Brian J. Conway,
                                       Managing Director


                                      -12-

 
                                     TA ASSOCIATES
                                     125 High Street, Suite 2500
                                     Boston, MA  02110
                                     Telecopy:  (617) 574-6728

                                 ADVENT VII L.P

                                 By: TA ASSOCIATES VII L.P., its General
                                     Partner
                                     
                                     By: TA ASSOCIATES, INC.,its
                                          General Partner
                                   
                                         By: /s/ Brian J. Conway
                                            _______________________  
                                            Brian J. Conway
                                            Managing Director

                                     TA ASSOCIATES
                                     125 High Street, Suite 2500
                                     Boston, MA  02110
                                     Telecopy:  (617) 574-6728

                                     TA VENTURE INVESTORS LIMITED
                                     PARTNERSHIP

                                     By: /s/ Brian J. Conway
                                        ___________________________
                                        Brian J. Conway,
                                        General Partner 

                                     TA ASSOCIATES
                                     125 High Street, Suite 2500
                                     Boston, MA  02110
                                     Telecopy:  (617) 574-6728

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