Sec. 27.63  Disturbance of AM broadcast station antenna patterns.

    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 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 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 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 WCS licensee is responsible for the installation and 
continued maintenance of any detuning apparatus necessary to restore 
proper performance of the AM station array.