§  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 SQRT P

   D (in miles) = 0.245 SQRT 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 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]