§  73.61   AM directional antenna field strength measurements.

   (a) Each AM station using a directional antenna with monitoring point
   locations specified in the instrument of authorization must make field
   strength measurements as often as necessary to ensure that the field at
   each of those points does not exceed the value specified in the station
   authorization. Additionally, stations not having an approved sampling
   system must make the measurements once each calendar quarter at
   intervals not exceeding 120 days. The provision of this paragraph
   supersedes any schedule specified on a station license issued prior to
   January 1, 1986. The results of the measurements are to be entered into
   the station log pursuant to the provisions of § 73.1820.

   (b) If the AM license was granted on the basis of field strength
   measurements performed pursuant to § 73.151(a), partial proof of
   performance measurements using the procedures described in § 73.154 must
   be made whenever the licensee has reason to believe that the radiated
   field may be exceeding the limits for which the station was most
   recently authorized to operate.

   (c) A station may be directed to make a partial proof of performance by
   the FCC whenever there is an indication that the antenna is not
   operating as authorized.

   [ 50 FR 47054 , Nov. 14, 1985, as amended at  73 FR 64560 , Oct. 30, 2008]