Sec. 73.318  FM blanketing interference.

    Areas adjacent to the transmitting antenna that receive a signal 
with a strength of 115 dBu (562 mV/m) or greater will be assumed to be 
blanketed. In determining the blanketed area, the 115 dBu contour is 
determined by calculating the inverse distance field using the effective 
radiated power of the maximum radiated lobe of the antenna without 
considering its vertical radiation pattern or height. For directional 
antennas, the effective radiated power in the pertinent bearing shall be 
used.
    (a) The distance to the 115 dBu contour is determined using the 
following equation:

D (in kilometers)=0.394 P
D (in miles)=0.245 P

Where P is the maximum effective radiated power (ERP), measured in 
kilowatts, of the maximum radiated lobe.
    (b) After January 1, 1985, permittees or licensees who either (1) 
commence program tests, or (2) replace their antennas, or (3) request 
facilities modifications and are issued a new construction permit must 
satisfy all complaints of blanketing interference which are received by 
the station during a one year period. The period begins with the 
commencement of program tests, or commencement of programming utilizing 
the new antenna. Resolution of complaints shall be at no

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cost to the complainant. These requirements specifically do not include 
interference complaints resulting from malfunctioning or mistuned 
receivers, improperly installed antenna systems, or the use of high gain 
antennas or antenna booster amplifiers. Mobile receivers and non-RF 
devices such as tape recorders or hi-fi amplifiers (phonographs) are 
also excluded.
    (c) A permittee collocating with one or more existing stations and 
beginning program tests on or after January 1, 1985, must assume full 
financial responsibility for remedying new complaints of blanketing 
interference for a period of one year. Two or more permittees that 
concurrently collocate on or after January 1, 1985, shall assume shared 
responsibility for remedying blanketing complaints within the blanketing 
area unless an offending station can be readily determined and then that 
station shall assume full financial responsibility.
    (d) Following the one year period of full financial obligation to 
satisfy blanketing complaints, licensees shall provide technical 
information or assistance to complainants on remedies for blanketing 
interference.

[ 28 FR 13623 , Dec. 14, 1963, as amended at  52 FR 25866 , July 9, 1987]