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                 RADIO ONE, INC., BELL BROADCASTING COMPANY and
                           RADIO ONE OF DETROIT, INC.

                                       and

               UNITED STATES TRUST COMPANY OF NEW YORK, as Trustee

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

                          FIRST SUPPLEMENTAL INDENTURE

                            Dated as of June 30, 1998

                                       to

                                    INDENTURE

                            Dated as of May 15, 1997

                                  by and among

                           RADIO ONE, INC., as Issuer

                                       and

               UNITED STATES TRUST COMPANY OF NEW YORK, as Trustee

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

                                   $85,478,000

                      12% Senior Subordinate Notes Due 2004

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     FIRST SUPPLEMENTAL  INDENTURE dated as of June 30, 1998, by and among RADIO
ONE, INC. ("ROI" or the "Company"),  a Delaware  corporation,  BELL BROADCASTING
COMPANY ("Bell"), a Michigan corporation,  RADIO ONE OF DETROIT, INC. ("ROD"), a
Delaware  corporation,  and  UNITED  STATES  TRUST  COMPANY  OF  NEW  YORK  (the
"Trustee").

     WHEREAS,  the Company  heretofore  executed and delivered to the Trustee an
Indenture dated as of May 15, 1997 (the "Indenture"), providing for the issuance
of  $85,478,000   aggregate   principal  amount  of  the  Company's  12%  Senior
Subordinated Notes Due 2004 (the "Notes"); and

     WHEREAS, Bell is a wholly owned subsidiary of ROI and ROD is a wholly owned
subsidiary of Bell; and

     WHEREAS,  Bell and ROD  desire  by this  First  Supplemental  Indenture  to
expressly become Subsidiary  Guarantors bound by the Subsidiary Guarantee of the
Securities set forth in Article 11 of the Indenture; and

     WHEREAS,  the execution and delivery of this First  Supplemental  Indenture
has been  authorized by  resolutions  of the Board of Directors of Bell and ROD;
and

     WHEREAS,  all  conditions  and  requirements  necessary  to make this First
Supplemental  Indenture a valid, binding and legal instrument in accordance with
its terms  have been  performed  and  fulfilled  by the  parties  hereto and the
execution and delivery  thereof have been in all respects duly authorized by the
parties hereto.

     NOW, THEREFORE,  in consideration of the above premises, each party agrees,
for the  benefit  of the  other and for the equal  and  ratable  benefit  of the
Holders of the Notes, as follows:


                                    ARTICLE 1

                            ASSUMPTION OF OBLIGATIONS

     Section 1.01.  Assumption.  Bell and ROD hereby  expressly  agree to become
Subsidiary Guarantors of the Securities set forth in Article 11 of the Indenture
and to assume all such Obligations (as such term is defined in the Indenture) as
set forth in Article 11 of the Indenture.  Any Notes delivered after the date of
this First Supplemental Indenture,  including Notes delivered in substitution or
exchange  for any  outstanding  Notes,  as  provided  in the  Indenture,  may be
executed and delivered by Radio One, Inc. in its own name,  with such notations,
legends or endorsements required by law, stock exchange rules or usage, and each
such Note shall constitute the obligation of Bell and ROD.


                                   ARTICLE II

                            MISCELLANEOUS PROVISIONS

     Section 2.01.  Terms Defined.  For all purposes of this First  Supplemental
Indenture, except as otherwise defined or unless the context otherwise requires,
terms used in capitalized form in this First Supplemental  Indenture and defined
in the Indenture have the meanings specified in the Indenture.

     Section 2.02.  Indenture.  Except as amended hereby,  the Indenture and the
Notes are in all respects  ratified and confirmed and all the terms shall remain
in full force and effect.

     Section 2.03.  Governing Law. THIS FIRST  SUPPLEMENTAL  INDENTURE  SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE  WITH THE LAWS OF THE STATE OF NEW YORK,
AS APPLIED TO CONTRACTS MADE AND PERFORMED  WITHIN THE STATE OF NEW YORK WITHOUT
REGARD TO PRINCIPLES OF CONFLICT OF LAWS.  Each of the parties  hereto agrees to
submit to the  jurisdiction of the courts of the State of New York in any action
or proceeding arising out of or relating to this First  Supplemental  Indenture,
provided that such jurisdiction shall be non-exclusive.






     Section  2.04.  Successors.  All  agreements  of Bell and ROD in this First
Supplemental  Indenture and the Notes shall bind its successors.  All agreements
of the Trustee in this Indenture shall bind its successor.

     Section  2.05.  Multiple  Counterparts.   The  parties  may  sign  multiple
counterparts of this First Supplemental Indenture. Each signed counterpart shall
be deemed an original, but all of them together represent the same agreement.

     Section 2.06.  Effectiveness.  The  provisions  of this First  Supplemental
Indenture  will take effect  immediately  upon its execution and delivery by the
Trustee and satisfaction with all of the conditions set forth in Section 4.12 of
the Indenture.

     Section 2.07. Trustee Disclaimer.  The Trustee accepts the amendment of the
Indenture  effected by this First  Supplemental  Indenture and agrees to execute
the trust  created by the  Indenture  and agrees to execute the trust created by
the  Indenture as hereby  amended,  but only upon the terms and  conditions  set
forth in the Indenture, including the terms and provisions defining and limiting
the liabilities and responsibilities of the Trustee,  which terms and provisions
shall in like manner define and limit its  liabilities and  responsibilities  in
the  performance  of the trust created by the Indenture as hereby  amended,  and
without  limiting the  generality  of the  foregoing,  the Trustee  shall not be
responsible in any manner  whatsoever for or with respect to any of the recitals
or statements  contained  herein,  all of which  recitals or statements are made
solely  by  Bell  and  ROD,  or for or  with  respect  to (i)  the  validity  or
sufficiency  of  this  First  Supplemental  Indenture  or any of  the  terms  or
provisions  hereof,  (ii) the  proper  authorization  hereof  by Bell and ROD by
corporate  action or otherwise,  (iii) the due execution hereof by Bell and ROD,
(iv) the consequences (direct or indirect and whether deliberate or inadvertent)
of any amendment  hereby  provided for, and the Trustee makes no  representation
with respect to any such matters.






                                   SIGNATURES

     IN WITNESS WHEREOF,  the parties hereto have caused this First Supplemental
Indenture to be duly executed as of the date first written above.

                                          Radio One, Inc.

                                          By: /s/ Alfred C. Liggins
                                             -----------------------------------
                                                   Name:    Alfred C. Liggins
                                                   Title:   President

                                          Bell Broadcasting Company

                                          By: /s/ Alfred C. Liggins
                                             -----------------------------------
                                                   Name:    Alfred C. Liggins
                                                   Title:   President

                                          Radio One of Detroit, Inc.

                                          By: /s/ Alfred C. Liggins
                                             -----------------------------------
                                                   Name:    Alfred C. Liggins
                                                   Title:   President

Attest: /s/ Scott R.  Royster
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                                          UNITED STATES TRUST COMPANY of
                                          NEW YORK, as Trustee

                                          By:
                                             -----------------------------------
                                                   Name:
                                                   Title: