Sec.  73.1665   Main transmitters.

   (a) Each AM, FM, TV and Class A TV broadcast station must have at least one
   main transmitter which complies with the provisions of the transmitter
   technical requirements for the type and class of station. A main transmitter
   is one which is used for regular program service having power ratings
   appropriate for the authorized operating power(s).

   (b) There is no maximum power rating limit for FM, TV or Class A TV station
   transmitters, however, the maximum rated transmitter power of a main
   transmitter stalled at an AM station shall be as follows:


------------------------------------------------------------------------
                                                               Maximum
                                                                rated
                      Authorized power                       transmitter
                                                              power (kW)
------------------------------------------------------------------------
0.25, 0.5, or 1 kW.........................................            1
2.5 kW.....................................................            5
5 or 10 kW.................................................           10
25 or 50 kW................................................           50
------------------------------------------------------------------------

   (c) A licensee may, without further authority or notification to the FCC,
   replace an existing main transmitter or install additional main
   transmitter(s) for use with the authorized antenna if the replacement or
   additional transmitter(s) has been verified for compliance. Within 10 days
   after commencement of regular use of the replacement or additional
   transmitter(s), equipment performance measurements, as prescribed for the
   type of station are to be completed.

   Note to paragraph (c): Pending the availability of AM broadcast transmitters
   that are approved or verified for use in the 1605–1705 kHz band,
   transmitters that are approved or verified for use in the 535–1605 kHz band
   may be utilized in the 1605–1705 kHz band if it is shown that the
   requirements of  Sec. 73.44 have been met. Verification or FCC approval of the
   transmitter will supersede the applicability of this note.

   [ 43 FR 53741 , Nov. 17, 1978, as amended at  47 FR 8590 , Mar. 1, 1982;  47 FR 28388 , June 30, 1982;  49 FR 4000 , Feb. 1, 1984;  51 FR 18451 , May 20, 1986;
    56 FR 64872 , Dec. 12, 1991;  63 FR 36604 , July 7, 1998;  65 FR 30004 , May 10,
   2000]