[C F R]
[Title 47, Volume 4, Parts 70 to 79]
[October 1, 1996]
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
D (in kilometers)= [ .394 times the square root of P ]
D (in miles)= [ .245 times the square root of 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
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