Sec.  73.1560   Operating power and mode tolerances.

   (a)  AM  stations. (1) Except as provided for in paragraph (d) of this
   section, the antenna input power of an AM station as determined by the
   procedures specified in  Sec. 73.51 must be maintained as near as is practicable
   to the authorized antenna input power and may not be less than 90% nor more
   than 105% of the authorized power.

   (2) Whenever the transmitter of an AM station cannot be placed into the
   specified operating mode at the time required, transmissions of the station
   must  be immediately terminated. However, if the radiated field at any
   bearing or elevation does not exceed that permitted for that time of day,
   operation in the mode with the lesser radiated field may continue under the
   notification procedures of paragraph (d) of this section.

   (b) FM stations. Except as provided in paragraph (d) of this section, the
   transmitter output power of an FM station, with power output as determined
   by the procedures specified in  Sec. 73.267, which is authorized for output power
   more  than  10  watts must be maintained as near as practicable to the
   authorized transmitter output power and may not be less than 90% nor more
   than 105% of the authorized power. FM stations operating with authorized
   transmitter output power of 10 watts or less, may operate at less than the
   authorized power, but not more than 105% of the authorized power.

   (c) TV stations. (1) Except as provided in paragraph (d) of this section,
   the visual output power of a TV or Class A TV transmitter, as determined by
   the procedures specified in Sec. 73.664, must be maintained as near as is
   practicable to the authorized transmitter output power and may not be less
   than 80% nor more than 110% of the authorized power.

   (2) The output power of the aural transmitter shall be maintained to provide
   an aural carrier ERP not to exceed 22% of the peak authorized visual ERP.

   (3) The FCC may specify deviation from the power of tolerance requirements
   for subscription television operations to the extent it deems necessary to
   permit proper operation.

   (d) Reduced power operation. In the event it becomes technically impossible
   to operate at authorized power, a broadcast station may operate at reduced
   power for a period of not more than 30 days without specific authority from
   the FCC. If operation at reduced power will exceed 10 consecutive days,
   notification must be made to the FCC in Washington, DC, Attention: Audio
   Division (radio) or Video Division (television), Media Bureau, not later
   than the 10th day of the lower power operation. In the event that normal
   power is restored within the 30 day period, the licensee must notify the FCC
   of the date that normal operation was restored. If causes beyond the control
   of the licensee prevent restoration of the authorized power within 30 days,
   a request for Special Temporary Authority (see  Sec. 73.1635) must be made to the
   FCC in Washington, DC for additional time as may be necessary.

   [ 44 FR 58734 , Oct. 11, 1979, as amended at  49 FR 22093 , May 25, 1984;  49 FR 29069 , July 18, 1984;  49 FR 47610 , Dec. 6, 1984;  50 FR 26568 , June 27, 1985;
    50 FR 40015 , Oct. 1, 1985;  63 FR 33877 , June 22, 1998;  65 FR 30004 , May 10,
   2000;  67 FR 13232 , Mar. 21, 2002]