<PAGE>   1
                                                                   EXHIBIT 4.3.7



                  WAIVER AND SIXTH AMENDMENT, dated as of March 11, 1998 (this
"SIXTH AMENDMENT"), to the AMENDED AND RESTATED CREDIT AGREEMENT, dated as of
November 19, 1996 (as amended, supplemented or otherwise modified from time to
time, the "CREDIT AGREEMENT"), among PAXSON COMMUNICATIONS CORPORATION, a
Delaware corporation (the "BORROWER"), the lenders from time to time party
thereto (the "LENDERS") and UNION BANK OF CALIFORNIA, N.A., as Agent.

                              W I T N E S S E T H :
                              - - - - - - - - - -
                 
                  WHEREAS, the Borrower has requested that the Lenders agree to
amend certain provisions of the Credit Agreement in connection with the
Borrower's sale of its radio and radio related businesses to Clear Channel
Communications, Inc. and its affiliates and the launch of its new network
PAXnet.

                  WHEREAS, the Lenders are willing to amend certain provisions
of the Credit Agreement but only on the terms and subject to the conditions
contained herein;

                  NOW, THEREFORE, in consideration of the premises and of the
mutual agreements herein contained, the parties hereto agree as follows:

                  1. DEFINITIONS. Unless otherwise defined herein, terms defined
in the Credit Agreement shall be used as so defined.

                  2. WAIVERS. The Lenders hereby waive: (i) subsection 2.6(d) of
the Credit Agreement to the extent necessary such that Net Cash Proceeds from
the Radio Group Sale do not have to be applied to prepay the Loans or reduce the
Commitments, (ii) subsection 6.1(e) of the Credit Agreement in respect of the
fiscal year ended December 31, 1997, and (iii) subsections 2.6(d) and 6.7 of the
Credit Agreement in respect of the sale of WOAC (Cleveland) so long as the
purchase price therefor is at least $23,000,000.

                  3. AMENDMENTS TO CREDIT AGREEMENT. The provisions contained in
this Section 2 of this Sixth Amendment shall be effective until and including
December 31, 1998, at which time the amendments to the Credit Agreement
contained in this Section 2 of this Sixth Amendment shall cease to be in effect
and the provisions of the Credit Agreement amended by this Section 2 of this
Sixth Amendment shall be in effect as such provisions were in effect prior to
this Sixth Amendment, except as such provisions may be amended, modified or
supplemented subsequent to the date hereof in accordance with the Credit
Agreement.

                     A. Subsection 1.1 of the Credit Agreement is hereby amended
by substituting the following definitions in alphabetical order in lieu of the
current definitions of such terms:

                     "`ADJUSTED CONSOLIDATED OPERATING CASH FLOW': (a) at any
                  date on or prior to December 31, 1998, the sum of (i) the
                  Consolidated Operating Cash Flow of the Borrower and its
                  Subsidiaries for the twelve most recently ended calendar
                  months for


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                  which the Lenders shall have received financial statements
                  pursuant to subsection 5.1(b)(i), MINUS (ii) Consolidated
                  Operating Cash Flow of the INTV Properties for such
                  twelve-month period, PLUS (iii) the product of (x) four times
                  (y) the Consolidated Operating Cash Flow of the INTV
                  Properties for the three most recently ended calendar months
                  for which the Lenders shall have received financial statements
                  pursuant to subsection 5.1(b)(i), PLUS (iv) up to $6,400,000
                  in start up costs paid by the Borrower or its Subsidiaries
                  related to the marketing of the launch of the new television
                  network planned by the Borrower (expected to be named PAXnet);
                  PLUS (v) up to $9,700,000 in management bonuses paid in the
                  fourth quarter of the 1997 fiscal year of the Borrower in
                  connection with the Radio Group Sale and (b) at any date after
                  December 31, 1998, Consolidated Operating Cash Flow of the
                  Borrower and its Subsidiaries.

                     `CONSOLIDATED CASH INTEREST EXPENSE': for any period, the
                  sum of (a) Consolidated Interest Expense of the Borrower and
                  its Subsidiaries, but excluding, however, amortization of
                  discount, deferred financing costs and other items included in
                  interest expense not payable or not actually paid in cash
                  during such period (including, but not limited to, any
                  interest on the Exchange Debentures paid in kind) MINUS (b)
                  the total interest income received by the Borrower and its
                  Subsidiaries on a consolidated basis for such period.

                     `LEVERAGE RATIO': at any date of determination, the ratio
                  of (a) Consolidated Total Debt of the Borrower and its
                  Subsidiaries on such date MINUS the amount of unencumbered
                  (other than encumbrances granted pursuant to the Loan
                  Documents) cash and Cash Equivalents held by the Borrower and
                  its Subsidiaries (or, in respect of December 31, 1997, cash
                  and Cash Equivalents held by the qualified intermediary
                  previously identified for the Lenders) on such date of
                  determination in excess of $5,000,000 to (b) Adjusted
                  Consolidated Operating Cash Flow as of the last day of the
                  month for which the Borrower shall have then most recently
                  delivered financial statements pursuant to subsection
                  5.1(b)(i).

                     `CONSOLIDATED FIXED CHARGES': for any period, without
                  duplication, the sum of (i) Consolidated Debt Service, PLUS
                  (ii) Consolidated Capital Expenditures to the extent actually
                  made, PLUS (iii) to the extent actually paid in cash during
                  such period, income tax expense (other than, to the extent
                  otherwise included therein, current income tax expenses
                  attributable to gains on Asset Sales) PLUS (iv) the aggregate
                  amount paid in cash during such period in connection with any
                  (A) dividend or other distribution or (B) redemption,
                  retirement, sinking fund or similar payment, purchase or other
                  acquisition for value, direct or indirect, on account of any
                  preferred capital stock (including, but not limited to, in
                  respect of Cumulative Preferred Stock or Exchangeable
                  Preferred Stock) of the Borrower or its Subsidiaries now or
                  hereafter outstanding, PROVIDED that to the extent any
                  redemption, retirement, sinking fund or similar payment,
                  purchase or other acquisition for value is made on the
                  Cumulative Preferred Stock prior to December 31, 1997, or any
                  dividend is paid in connection therewith, the amount expended
                  in connection therewith shall be


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                  excluded from any calculations pursuant to this definition
                  MINUS (v) the total interest income received by the Borrower
                  and its Subsidiaries on a consolidated basis for such period."

                     B. Section 5 of the Credit Agreement is hereby amended by
inserting at the end of such Section the following subsection 5.15:

                     "5.15 ISSUANCE OF CAPITAL STOCK. Prior to May 31, 1998, the
                  Borrower shall use its best efforts to issue Capital Stock
                  (common or preferred) on terms and conditions satisfactory to
                  the Agent for aggregate proceeds of at least $150,000,000 and
                  immediately apply the Net Cash Proceeds thereof to prepay the
                  Loans."

                     C. Subsection 6.1(b) of the Credit Agreement is hereby
amended by deleting the table therein and substituting in lieu thereof the
following new table:

================================================================================
                                                        CASH INTEREST
             PERIOD                                     COVERAGE RATIO
================================================================================
--------------------------------------------------------------------------------
October 1, 1997 - December 31, 1997                        1.15:1.00
--------------------------------------------------------------------------------
January 1, 1998 - June 30, 1998                            1.25:1.00
--------------------------------------------------------------------------------
July 1, 1998 - December 31, 1998                           1.50:1.00
--------------------------------------------------------------------------------
Thereafter                                                 2.00:1.00
================================================================================

                     D. Subsection 6.1(d) of the Credit Agreement is hereby
amended by deleting such Subsection in its entirety and substituting in lien
thereof the following:

                     "FIXED CHARGE COVERAGE. Permit the ratio of (y) Adjusted
                  Consolidated Operating Cash Flow to (z) Consolidated Fixed
                  Charges of the Borrower and its Subsidiaries for the twelve
                  consecutive month period ending as of the last day of any
                  calendar quarter to be less than 1.00:1.00 with respect to any
                  calendar quarter ended on or prior to June 30, 1998 and
                  1.10:1.00 with respect to any calendar quarter ended
                  thereafter."

                     E. Subsection 6.2 of the Credit Agreement is hereby amended
by inserting immediately at the end of such subsection the following:

                     "PROVIDED, that after February 25, 1998 neither the
                  Borrower nor any of its Subsidiaries shall directly or
                  indirectly create, incur, assume, guaranty or otherwise become
                  directly or indirectly liable with respect to any Indebtedness
                  not outstanding on such date as Indebtedness of the Borrower
                  or any of its Subsidiaries, other than Capital Stock issued
                  pursuant to subsection 5.15 and Indebtedness incurred or
                  issued pursuant to subsection 6.2(j)."




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                     F. Schedule 1.1C of the Credit Agreement is hereby amended
by deleting such Schedule in its entirety and substituting in lieu thereof Annex
A hereto. 

                  4. AMENDMENT FEE. The Borrower hereby agrees to pay a fee in
an amount equal to 0.25% of such Lender's Commitment to each Lender that
approves this Sixth Amendment by executing and delivering to the Administrative
Agent or its counsel said Amendment on or before March 11, 1998.

                  5. EFFECTIVE DATE. This Sixth Amendment will become effective
as of the date (the "EFFECTIVE DATE") hereof upon (i) its execution by the
Borrower and the Required Lenders in accordance with the terms of the Credit
Agreement and (ii) the execution and delivery by the Borrower to the
Administrative Agent for the benefit of the Lenders of a cash collateral
agreement in form and substance satisfactory to the Lenders and the deposit by
the Borrower in the cash collateral account provided for therein of $17,000,000
to be applied to the payment of interest due pursuant to the Credit Agreement
and as Collateral for the Obligations.

                  6. REPRESENTATIONS AND WARRANTIES. The Borrower represents and
warrants to each Lender that (a) this Sixth Amendment constitutes the legal,
valid and binding obligation of the Borrower, enforceable against it in
accordance with its terms, except as such enforcement may be limited by
bankruptcy, insolvency, fraudulent conveyances, reorganization, moratorium or
similar laws affecting creditors' rights generally, by general equitable
principles (whether enforcement is sought by proceedings in equity or at law)
and by an implied covenant of good faith and fair dealing, (b) the
representations and warranties made by the Loan Parties in the Loan Documents
are true and correct in all material respects on and as of the date hereof
(except to the extent that such representations and warranties are expressly
stated to relate to an earlier date, in which case such representations and
warranties shall have been true and correct in all material respects on and as
of such earlier date) and (c) no Default or Event of Default has occurred and is
continuing as of the date hereof.

                  7. CONTINUING EFFECT. Except as expressly waived or amended
hereby, the Credit Agreement shall continue to be and shall remain in full force
and effect in accordance with its terms. This Sixth Amendment (and all
amendments to and waivers in respect of the Credit Agreement and other Loan
Documents) shall be deemed to be a Loan Document.

                  8. GOVERNING LAW. THIS SIXTH AMENDMENT SHALL BE GOVERNED BY,
AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW
YORK.

                  9. COUNTERPARTS. This Sixth Amendment may be executed by the
parties hereto in any number of separate counterparts and all of said
counterparts taken together shall be deemed to constitute one and the same
instrument.





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                  10. PAYMENT OF EXPENSES. The Borrower agrees to pay and
reimburse the Agent for all of its out-of-pocket costs and reasonable expenses
incurred in connection with this Sixth Amendment, including, without limitation,
the reasonable fees and disbursements of counsel to the Agent.



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                  IN WITNESS WHEREOF, the parties hereto have caused this Sixth
Amendment to be duly executed and delivered by their properly and duly
authorized officers as of the day and year first above written.



                                        PAXSON COMMUNICATIONS
                                        CORPORATION


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



                                        UNION BANK OF CALIFORNIA, N.A., as
                                        Agent


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



                                        THE BANK OF NEW YORK


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



                                        CIBC, INC.


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



                                        BANKBOSTON, N.A.


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



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                                                                               7


                                        ABN-AMRO BANK N.V.
                                        ABN AMRO NORTH AMERICA, INC.


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



                                        BANK OF AMERICA NT&SA


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



                                        BANK OF MONTREAL


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



                                        BARNETT BANK, N.A.


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



                                        FLEET NATIONAL BANK


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





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                                        LTCB TRUST COMPANY


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



                                        THE SUMITOMO BANK, LIMITED


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


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



                                        SUNTRUST BANK, CENTRAL FLORIDA, N.A.


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