§  27.63   Disturbance of AM broadcast station antenna patterns.

   AWS and WCS licensees that construct or modify towers in the immediate
   vicinity of AM broadcast stations are responsible for measures
   necessary to correct disturbance of the AM station antenna pattern
   which causes operation outside of the radiation parameters specified by
   the FCC for the AM station, if the disturbance occurred as a result of
   such construction or modification.

   (a) Non-directional AM stations. If tower construction or modification
   is planned within 1 kilometer (0.6 mile) of a non-directional AM
   broadcast station tower, the AWS or WCS licensee must notify the
   licensee of the AM broadcast station in advance of the planned
   construction or modification. Measurements must be made to determine
   whether the construction or modification would affect the AM station
   antenna pattern. The AWS or WCS licensee is responsible for the
   installation and continued maintenance of any detuning apparatus
   necessary to restore proper non-directional performance of the AM
   station tower.

   (b) Directional AM stations. If tower construction or modification is
   planned within 3 kilometers (1.9 miles) of a directional AM broadcast
   station array, the AWS or WCS licensee must notify the licensee of the
   AM broadcast station in advance of the planned construction or
   modification. Measurements must be made to determine whether the
   construction or modification would affect the AM station antenna
   pattern. The AWS or WCS licensee is responsible for the installation
   and continued maintenance of any detuning apparatus necessary to
   restore proper performance of the AM station array.

   [ 69 FR 5715 , Feb. 6, 2004]