CONFIDENTIAL TREATMENT REQUESTED

     Confidential Portions of This Agreement Which Have Been Redacted Are Marked
With Brackets ("[***]"). The Omitted Material Has Been Filed Separately With The
Securities and Exchange Commission.


                           SITE DEVELOPMENT AGREEMENT


     THIS SITE DEVELOPMENT AGREEMENT ("Agreement"),  dated as of the 17th day of
August,  1999  ("Effective  Date"),  is made  by and  between  Horizon  Personal
Communications,  Inc.  ("Horizon") and SBA Towers,  Inc., a Florida  corporation
("SBA").

     WHEREAS,  Horizon Telecom, Inc., Horizon and SBA have entered into an Asset
Purchase Agreement ("APA") whereby SBA will purchase certain  telecommunications
tower sites from  Horizon,  and Horizon and SBA have entered into or have agreed
to enter  into a Master  Site  Agreement  ("MSA"),  and a  Master  Design  Build
Agreement   ("BTS   Agreement")   whereby   SBA   will   construct    additional
telecommunications  tower sites to Horizon's  specifications,  and Horizon shall
lease space on such towers from SBA; and

     WHEREAS,   Horizon  controls  certain  affiliated  companies  and/or  makes
managerial  decisions for certain  affiliated  companies,  including Bright PCS,
LLC, regarding the construction of future telecommunications tower sites and has
agreed on behalf of certain  of such  affiliates  to enter into a  build-to-suit
agreement  ("Affiliate BTS  Agreement")  and a lease-back  agreement with SBA on
behalf of such affiliates on substantially  the same terms and conditions as the
BTS Agreement and the Master Site Agreement; and

     WHEREAS,  as a  material  inducement  to  Horizon  to enter  into the Asset
Purchase  Agreement,  Master Site  Agreement and BTS Agreement SBA has agreed to
pay certain  development  fees to Horizon for certain  telecommunications  tower
sites which SBA constructs on behalf of Horizon or its affiliates.

     NOW THEREFORE,  for and in consideration of the mutual covenants  contained
herein and other good and valuable  consideration,  the parties  hereby agree as
follows:

     1. DEFINITION OF REGIONS.  As used herein,  "Region 1" shall mean BTA's 23,
39, 73, 78, 80, 126,  143, 155, 197, 233, 255, 280, 294, 342, 359, 424, and 487,
and any counties  which are adjacent to these BTAs.  As used herein,  "Region 2"
shall mean BTA 229.

     2. TERM.  This agreement  shall commence upon the effective date of the BTS
Agreement  and shall  continue in fall force and effect until the  expiration or
earlier  termination  of the BTS Agreement or the  Affiliate  BTS  Agreement(s),
whichever occurs later.

     3. DEVELOPMENT  FEES. As consideration  for Horizon's  services relating to
providing  build-to-suit  opportunities,  SBA shall, within ten (10) days of the
SLA  Commencement  Date (as that term is  defined  in the MSA) for each BTS Site
constructed  by SBA under the BTS Agreement or any of the Affiliate  Agreements,


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<PAGE>
                                        [***] - CONFIDENTIAL TREATMENT REQUESTED

pay to Horizon at the address set forth in  paragraph 5 below,  the sum of [***]
for the applicable  Site in Region 1, the sum of [***] for the first [***] Sites
constructed  in  Region  2 in the  aggregate  under  the BTS  Agreement  and the
Affiliate  BTS  Agreement(s),  and the sum of [***]  for each  Site in  Region 2
beyond the initial [***] ("Development  Fee"). In the event that the Development
Fee for a Site is not paid within ten (10) days of the SLA Commencement Date for
that Site,  Horizon  shall be entitled  to offset  such amount  against the Rent
payable under the MSA and related SLAs.

     4.  PUBLICITY.  Neither  party  shall  make news  releases  or issue  other
advertising  pertaining to the Services or this Agreement  without prior written
approval of the other  party;  provided,  however,  that both  parties  agree to
either approve or deny such news release or advertising  within two (2) business
days of the request for approval  from the other  party.  In the event that such
news  release or  advertising  is  neither  approved  nor denied  within two (2)
business days, it shall be deemed approved.

     5.  NOTICES.  All  notices or other  communications  hereunder  shall be in
writing  and shall be deemed to have been  duly  delivered  and  effective  upon
receipt if personally  delivered,  or on receipt if mailed by prepaid  overnight
express  service,  addressed to the following (or other addresses as the parties
hereto may designate):

     If to Horizon, to:                        If to SBA, to:

     Horizon Personal Communications, Inc.     SBA
     68 East Main Street                       SBA Towers, Inc.
     P.O. Box 480                              One Town Center Road, 34 Floor
     Chillicothe, Ohio 45601-0480              Boca Raton, FL 33462
     Attn: Vice President Technology           Attn: General Counsel

     6. BINDING EFFECT.  The Agreement shall be binding upon and enforceable by,
and  inure to the  benefit  of,  successors,  assigns,  and  transferees  of the
parties.

     7. FURTHER  ASSURANCES.  The parties shall execute and deliver such further
instruments and perform such further acts as may reasonably be required to carry
out the intent and purposes of this Agreement.

     8. CHOICE OF LAW.  The  Agreement  shall be governed  by and  construed  in
accordance  with the laws of the State of Ohio,  excluding  the  conflict of law
provisions thereof.

     9. WAIVER. The failure of either party to insist upon strict performance of
any  obligation  hereunder,  irrespective  of the  length of time for which such
failure  continue,  shall not be a waiver of such party's right to demand strict
compliance in the future. No consent or waiver, express or implied, to or of any
breach  or  default  in  the  performance  of  any  obligation  hereunder  shall
constitute  a consent  or waiver to or of any  other  breach or  default  in the
performance of the same or any other obligation hereunder.

     10.  HEADINGS.  All section and paragraph  titles or captions  contained in
this Agreement are for convenience only and shall not be deemed part of the text
of this Agreement.



                                       2
<PAGE>

     11.  PRONOUNS.  All pronouns and any variations  thereof shall be deemed to
refer to the masculine, feminine, neuter, singular, or plural as the context may
require.

     12.   COUNTERPARTS.   This  Agreement  may  be  signed  in  any  number  of
counterparts,  each of which shall be  considered  an original  and all of which
taken together shall constitute one and the same instrument.

     13.  CONSTRUCTION  OF  AGREEMENT.   This  Agreement  shall  be  interpreted
according  to its plain  meeting  and shall not be  strictly  construed  against
either party.

     14.  CONFIDENTIAL INFORMATION.

          (a) Use of Confidential Information. In order to permit the parties to
perform their respective obligations under this Agreement,  each party may, from
time to time,  disclose to the other  confidential  or proprietary  information.
Such  confidential  or proprietary  information  and the terms of this Agreement
shall  constitute   "Confidential   Information".   Each  party  shall  use  all
Confidential  Information  solely for the purpose of performing its  obligations
under this  Agreement.  Neither party shall disclose to any other person,  other
than employees or agents of the party who agree,  in writing,  to be bound by an
equivalent undertaking, any Confidential Information. SBA agrees not to disclose
any of Horizon's  Confidential  Information or any information pertaining to the
Sites to a competitor  of Horizon.  Horizon  agrees not to disclose any of SBA's
Confidential  Information  or  any  information  pertaining  to the  Sites  to a
competitor of SBA.

          (b) Exceptions.  The  aforementioned  restrictions  shall apply to all
Confidential Information with the exception
of the following:

                    (i) Confidential  Information which is made public by either
          party while  performing  under this Agreement or which otherwise is or
          hereafter  becomes part of the public domain  through no wrongful act,
          fault, or negligence on the part of the other party;

                    (ii)  Confidential  Information which a party can reasonably
          demonstrate  is already in such party's  possession and not subject to
          an existing agreement of confidentiality;

                    (iii)  Confidential  Information  which is  received  from a
          third party  without  restriction  and without  breach of an agreement
          with Horizon or SBA;

                    (iv)   Confidential   Information   which  is  independently
          developed by a party as evidenced by its records; or

                    (v) Confidential  Information which either party is required
          to disclose pursuant to a valid order of a court or other governmental
          body or any  political  subdivision  thereof;  provided  that,  to the
          extent that it may lawfully do so, the disclosing  party shall provide
          the affected party with immediate  written notice of the nature of the
          required  disclosure and shall, where appropriate,  provide that party
          with the  opportunity to interpose an objection or obtain a protective
          order   restricting  the  use  and  disclosure  of  the   Confidential
          Information; or

                    (vi) in defense of a legal action or otherwise required by a
          governmental agency or applicable law.

                                       3
<PAGE>

     15.  ENTIRE  AGREEMENT.  This  Agreement,  the APA,  the  MSA,  and the BTS
Agreement  contain  the entire  understanding  between and among the parties and
supersede any prior  understandings  and  agreements  among them  respecting the
subject matter of this Agreement.

     16.  CONDITIONS  PRECEDENT.  SBA  shall  have the right to  terminate  this
Agreement  if the  following  conditions  have not been  satisfied  prior to the
Closing  (as that  term is  defined  in the  APA):  1) a BTS  Agreement  in form
substantially  similar to this  Agreement  has been entered into between  Bright
PCS,  LLC and SBA;  and 2) this  Agreement  has been  approved  by the  Board of
Directors  of SBA.  In the  event  that SBA  fails to  obtain  approval  of this
Agreement  by its  Board of  Directors  on or before  September  1,  1999,  this
Agreement shall terminate and SBA shall pay to Horizon the sum of Fifty Thousand
and No/100 Dollars ($50,000.00).

     IN WITNESS  WHEREOF,  SBA and Horizon have duly executed and delivered this
Agreement. The party last executing this Agreement shall insert the date of such
execution  on the  first  page  hereof,  which  date  shall  be the Date of this
Agreement.

                                     SBA:

                                     SBA TOWERS, INC.

                                     By:________________________________

                                     Title:_____________________________

                                     Attest:____________________________


                                               (CORPORATE SEAL]

                                     HORIZON:

                                     HORIZON PERSONAL COMMUNICATIONS, INC.

                                     By:_________________________________

                                     Title:______________________________