Sec.  73.58   Indicating instruments.

   (a) Each AM broadcast station must be equipped with indicating instruments
   which conform with the specifications described in  Sec. 73.1215 for determining
   power by the direct and indirect methods, and with such other instruments as
   are necessary for the proper adjustment, operation, and maintenance of the
   transmitting system. However, auxiliary transmitters with a nominal power
   rating of 100 watts or less are not required to be equipped with instruments
   to determine power by the indirect method provided that the licensee can
   determine the antenna input power at all times.

   (b) Since it is usually impractical to measure the actual antenna current of
   a shunt excited antenna system, the current measured at the input of the
   excitation circuit feed line is accepted as the antenna current.

   (c) The function of each instrument shall be clearly and permanently shown
   on the instrument itself or on the panel immediately adjacent thereto.

   (d)  In the event that any one of these indicating instruments becomes
   defective when no substitute which conforms with the required specifications
   is available, the station may be operated without the defective instrument
   pending its repair or replacement for a period not in excess of 60 days
   without further authority of the Commission. If the defective instrument is
   the antenna current meter of a nondirectional station which does not employ
   a remote antenna ammeter, or if the defective instrument is the common point
   meter of a station which employs a directional antenna and does not employ a
   remote common point meter, the operating power shall be determined by a
   method described in  Sec. 73.51(a)(1) or  Sec. 73.51(d) during the entire time the
   station is operated without the antenna current meter or common point meter.
   However, if a remote meter is employed and the antenna current ammeter or
   common  point meter becomes defective, the remote meter can be used to
   determine operating power pending the return to service of the regular
   meter.

   (e) If conditions beyond the control of the licensee prevent the restoration
   of  the  meter to service within the above allowed period, information
   requested in accordance with  Sec. 73.3549 may be filed by letter with the FCC in
   Washington,  DC,  Attention:  Audio Division, Media Bureau, to request
   additional time as may be required to complete repairs of the defective
   instrument.

   [ 41 FR 36817 , Sept. 1, 1976, as amended at  48 FR 38477 , Aug. 24, 1983;  49 FR 49850 , Dec. 24, 1984;  50 FR 32416 , Aug. 12, 1985;  51 FR 2707 , Jan. 21, 1986;
    53 FR 2498 , Jan. 28, 1988;  63 FR 33876 , June 22, 1998;  66 FR 20755 , Apr. 25,
   2001;  67 FR 13231 , Mar. 21, 2002]