Sec. 73.1670  Auxiliary transmitters.

    (a) A licensee of a broadcast station may, without further authority 
from the FCC, install and use with the main antenna system one or more 
auxiliary transmitters for the following purposes:
    (1) The transmission of regular programs upon failure of the main 
transmitter.
    (2) The transmission of regular programs during maintenance or 
modification of the main transmitter.
    (3) Emergency broadcast system operation.
    (4) The transmission of regular programs by an AM station authorized 
for Presunrise (PSRA) and/or Postsunset (PSSA) operation.
    (5) The transmission of tests to determine the operating condition 
of the auxiliary transmitter or auxiliary antenna.
    (6) For testing, upon the request of representatives of the FCC.
    (b) Authorization to install an auxiliary transmitter for use with 
other than the main antenna or authorized auxiliary antenna must be 
obtained by filing an application for a construction permit on FCC form 
301 (FCC form 340 for noncommercial educational stations).
    (c) The following technical and operating standards apply to 
auxiliary transmitters:
    (1) The auxiliary transmitter may be operated on only the station's 
authorized frequency and within the required carrier frequency departure 
tolerance for the type of station.
    (2) The carrier frequency of the auxiliary transmitter must be 
measured as often as necessary to ensure that it is maintained within 
the prescribed tolerance.
    (3) When using an auxiliary transmitter, the operating power may be 
less than the authorized power but may not exceed the authorized power 
within the permitted tolerance for the type of station. If operation 
with an auxiliary transmitter at reduced power continues for a period 
exceeding 10 days, the FCC in Washington, DC must be notified. (See 
Sec. 73.51, AM; Sec. 73.267, FM; Sec. 73.567, NCE-FM; and Sec. 73.663, 
TV).
    (4) Normal operator requirements apply to the operation of the 
auxiliary transmitter.

    Note: After January 1, 1979, new licenses will not be issued nor 
will existing licenses be renewed for auxiliary transmitters that are 
operated into the main antenna system.


[ 43 FR 53741 , Nov. 17, 1978, as amended at  44 FR 22740 , Apr. 17, 1979; 
 48 FR 36463 , Aug. 11, 1983;  48 FR 42960 , Sept. 20, 1983;  48 FR 44806 , 
Sept. 30, 1983;  50 FR 32417 , Aug. 12, 1985;  51 FR 32088 , Sept. 9, 1986]