Sec.  73.61   AM directional antenna field strength measurements.

   (a) Each AM station using a directional antenna must make field strength
   measurements at the monitoring point locations specified in the instrument
   of authorization, as often as necessary to ensure that the field at those
   points does not exceed the values 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  Sec. 73.1820.

   (b) Partial proof of performance measurements using the procedures described
   in  Sec. 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]