Goto Section: 74.703 | 74.706 | Table of Contents
FCC 74.705
Revised as of
Goto Year:1996 |
1998
Sec. 74.705 TV broadcast analog station protection.
(a) The TV broadcast station protected contour will be its Grade B
contour signal level as defined in Sec. 73.683 and calculated from the
authorized maximum radiated power (without depression angle correction),
the horizontal radiation pattern, height above average terrain in the
pertinent direction, and the appropriate chart from Sec. 73.699.
(b)(1) An application to construct a new low power TV or TV
translator station or change the facilities of an existing station will
not be accepted if it specifies a site which is within the protected
contour of a co-channel or first adjacent channel TV broadast station.
(2) Due to the frequency spacing which exists between TV Channels 4
and 5, between Channels 6 and 7, and between Channels 13 and 14,
adjacent channel protection standards shall not be applicable to these
pairs of channels. (See Sec. 73.603(a) of part 73 of this chapter.)
(3) A UHF low power TV or TV translator construction permit
application will not be accepted if it specifies a site within the UHF
TV broadcast station's protected contour and proposes operation on a
channel either 14 or 15 channels above the channel in use by the TV
broadcast station.
(4) A UHF low power TV or TV translator construction permit
application will not be accepted if it specifies a site less than 100
kilometers from the transmitter site of a UHF TV broadcast analog
station operating on a channel which is the seventh channel above the
requested channel, unless it
[[Page 430]]
can demonstrate that the service area of the low power TV or TV
translator station as established in Sec. 74.707(a) is not located in an
area where the TV broadcast analog station is regularly viewed.
(5) An application for a new UHF low power TV or TV translator
construction permit, a change of channel, or a major change in
facilities pursuant to Sec. 73.3572 of this chapter proposing a maximum
effective radiated power of more than 50 kilowatts will not be accepted
if it specifies a site less than 32 kilometers from the transmitter site
of a UHF TV broadcast analog station operating on a channel which is the
second, third, or fourth channel above or below the requested channel.
(c) The low power TV, TV translator, or TV booster station field
strength is calculated from the proposed effective radiated power (ERP)
and the antenna height above average terrain (HAAT) in pertinent
directions.
(1) For co-channel protection, the field strength is calculated
using Figure 9a, 10a, or 10c of Sec. 73.699 (F(50,10) charts) of Part 73
of this chapter.
(2) For low power TV, TV translator, and TV boosters that do not
specify the same channel as the TV broadcast station to be protected,
the field strength is calculated using Figure 9, 10, or 10b of
Sec. 73.699 (F(50,50) charts) of Part 73 of this chapter.
(d) A low power TV, TV translator, or TV booster station application
will not be accepted if the ratio in dB of its field strength to that of
the TV broadcast station at the protected contour fails to meet the
following:
(1) -45 dB for co-channel operations without offset carrier
frequency operation or -28 dB for offset carrier frequency operation. An
application requesting offset carrier frequency operation must include
the following:
(i) A requested offset designation (zero, plus, or minus)
identifying the proposed direction of the 10 kHz offset from the
standard carrier frequencies of the requested channel. If the offset
designation is not different from that of the station being protected,
the -45 dB ratio must be used.
(ii) A description of the means by which the low power TV, TV
translator, or TV booster station will be maintained within the
tolerances specified in Sec. 74.761 for offset operation.
(2) 6 dB when the protected TV broadcast station operates on a VHF
channel that is one channel above the requested channel.
(3) 12 dB when the protected TV broadcast station operates on a VHF
channel that is one channel below the requested channel.
(4) 15 dB when the protected TV broadcast station operates on a UHF
channel that is one channel above or below the requested channel.
(5) 23 dB when the protected TV broadcast station operates on a UHF
channel that is fourteen channels below the requested channel.
(6) 6 dB when the protected TV broadcast station operates a UHF
channel that is fifteen channels below the requested channel.
(e) In support of a request for waiver of the interference
protection rules, an applicant for a low power TV, TV translator or TV
booster may make full use of terrain shielding and Longley-Rice terrain
dependent propagation prediction methods to demonstrate that the
proposed facility would not be likely to cause interference to TV
broadcast stations. Guidance on using the Longley-Rice methodology is
provided in OET Bulletin No. 69. Copies of OET Bulletin No. 69 may be
inspected during normal business hours at the: Federal Communications
Commission, 1919 M St., NW., Dockets Branch (Room 239), Washington, DC
20554. This document is also available through the Internet on the FCC
Home Page at http://www.fcc.gov.
[ 47 FR 21497 , May 18, 1982, as amended at 48 FR 21487 , May 12, 1983; 52 FR 31403 , Aug. 20, 1987; 62 FR 26721 , May 14, 1997]
Goto Section: 74.703 | 74.706
Goto Year: 1996 |
1998
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