FCC 90.545 Revised as of October 1, 2006
Goto Year:2005 |
2007
Sec. 90.545 TV/DTV interference protection criteria.
Public safety base, control, and mobile transmitters in the 764–776 MHz and
794–806 MHz frequency bands must be operated only in accordance with the
rules in this section, to reduce the potential for interference to public
reception of the signals of existing TV and DTV broadcast stations
transmitting on TV Channels 62, 63, 64, 65, 67, 68 or 69.
(a) D/U ratios. Licensees of public safety stations must choose site
locations that are a sufficient distance from co-channel and adjacent
channel TV and DTV stations, and/or must use reduced transmitting power or
transmitting antenna height such that the following minimum desired signal
to undesired signal ratios (D/U ratios) are met:
(1) The minimum D/U ratio for co-channel stations is 40 dB at the
hypothetical Grade B contour (64 dB µV/m) (88.5 kilometers or 55.0 miles) of
the TV station or 17 dB at the equivalent Grade B contour (41 dB µV/m) (88.5
kilometers or 55.0 miles) of the DTV station.
(2) The minimum D/U ratio for adjacent channel stations is 0 dB at the
hypothetical Grade B contour (64 dB µV/m) (88.5 kilometers or 55.0 miles) of
the TV station or −23 dB at the equivalent Grade B contour (41 dB µV/m) (88.5
kilometers or 55.0 miles) of the DTV station.
(b) Maximum ERP and HAAT. The maximum effective radiated power (ERP) and the
antenna height above average terrain (HAAT) of the proposed land mobile base
station, the associated control station, and the mobile transmitters shall
be determined using the methods described in this section.
(1) Each base station is limited to a maximum ERP of 1000 watts.
(2) Each control station is limited to a maximum ERP of 200 watts and a
maximum HAAT of 61 m. (200 ft).
(3) Each mobile station is limited to a maximum ERP of 30 watts and a
maximum antenna height of 6.1 m. (20 ft.).
(4) Each portable (handheld) transmitter is limited to a maximum ERP of 3
watts.
(5) All transmitters are subject to the power reductions given in Figure B
of Sec. 90.309 of this chapter, for antenna heights higher than 152 meters (500
ft).
(c) Methods. The methods used to calculate TV contours and antenna heights
above average terrain are given in Sec. Sec. 73.683 and 73.684 of this chapter.
Tables to determine the necessary minimum distance from the public safety
station to the TV/DTV station, assuming that the TV/DTV station has a
hypothetical or equivalent Grade B contour of 88.5 kilometers (55.0 miles),
are located in Sec. 90.309 and labeled as Tables B, D, and E. Values between
those given in the tables may be determined by linear interpolation. The
locations of existing and proposed TV/DTV stations during the transition
period are given in Part 73 of this chapter and in the final proceedings of
MM Docket No. 87–268. The DTV allotments are:
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---------------------------------
State City NTSC TV Ch. DT
V Ch. ERP (kW) HAAT (m)
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---------------------------------
California.......................... Stockton.............. 64
62 63.5 874
California.......................... Los Angeles........... 11
65 688.7 896
California.......................... Riverside............. 62
68 180.1 723
California.......................... Concord............... 42
63 61.0 856
Pennsylvania........................ Allentown............. 39
62 50.0 302
Pennsylvania........................ Philadelphia.......... 6
64 1000.0 332
Pennsylvania........................ Philadelphia.......... 10
67 791.8 354
Puerto Rico......................... Aguada................ 50
62 50.0 343
Puerto Rico......................... Mayaguez.............. 16
63 50.0 347
Puerto Rico......................... Naranjito............. 64
65 50.0 142
Puerto Rico......................... Aguadilla............. 12
69 691.8 665
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The transition period is scheduled to end on December 31, 2006. After that
time, unless otherwise directed by the Commission, public safety stations
will no longer be required to protect reception of co-channel or adjacent
channel TV/DTV stations.
(1) Licensees of stations operating within the ERP and HAAT limits of
paragraph (b) must select one of three methods to meet the TV/DTV protection
requirements, subject to Commission approval:
(i) utilize the geographic separation specified in the tables referenced
below;
(ii) Submit an engineering study justifying the proposed separations based
on the parameters of the land mobile station and the parameters, including
authorized and/or applied for facilities, of the TV/DTV station(s) it is
trying to protect; or,
(iii) obtain written concurrence from the applicable TV/DTV station(s). If
this method is chosen, a copy of the agreement must be submitted with the
application.
(2) The following is the method for geographic separations.
(i) Base stations having an antenna height (HAAT) less than 152 m. (500 ft.)
shall afford protection to co-channel and adjacent channel TV/DTV stations
in accordance with the values specified in Table B (co-channel frequencies
based on 40 dB protection) and Table E (adjacent channel frequencies based
on 0 dB protection) in Sec. 90.309 of this part. For base stations having an
antenna height (HAAT) between 152–914 meters (500–3,000 ft.) the effective
radiated power must be reduced below 1 kilowatt in accordance with the
values shown in the power reduction graph in Figure B in Sec. 90.309 of this
part. For heights of more than 152 m. (500 ft.) above average terrain, the
distance to the radio path horizon will be calculated assuming smooth earth.
If the distance so determined equals or exceeds the distance to the
hypothetical or equivalent Grade B contour of a co-channel TV/DTV station
(i.e., it exceeds the distance from the appropriate Table in Sec. 90.309 to the
relevant TV/DTV station) an authorization will not be granted unless it can
be shown in an engineering study (method 2) that actual terrain
considerations are such as to provide the desired protection at the actual
Grade B contour (64 dB µV/m for TV and 41 dB µV/m for DTV stations), or that
the effective radiated power will be further reduced so that, assuming free
space attenuation, the desired protection at the actual Grade B contour (64
dB µV/m for TV and 41 dB µV/m coverage contour for DTV stations) will be
achieved. Directions for calculating powers, heights, and reduction curves
are listed in Sec. 90.309 for land mobile stations. Directions for calculating
coverage contours are listed in Sec. Sec. 73.683–685 for TV stations and in Sec. 73.625
for DTV stations.
(ii) Control and mobile stations (including portables) are limited in height
and power and therefore shall afford protection to co-channel and adjacent
channel TV/DTV stations in accordance with the values specified in Table D
(co-channel frequencies based on 40 dB protection) in Sec. 90.309 of this part
and a minimum distance of 8 kilometers (5 miles) from all adjacent channel
TV/DTV station hypothetical or equivalent Grade B contours (adjacent channel
frequencies based on 0 dB protection for TV stations and—23 dB for DTV
stations). Since control and mobile stations may affect different TV/DTV
stations than the associated base station, particular care must be taken by
applicants to ensure that all the appropriate TV/DTV stations are considered
(e.g., a base station may be operating on TV Channel 64 and the mobiles on
TV Channel 69, in which case TV Channels 63, 64, 65, 68, and 69 must be
protected). Since mobiles and portables are able to move and communicate
with each other, licensees or coordinators must determine the areas where
the mobiles can and cannot roam in order to protect the TV/DTV stations, and
advise the mobile operators of these areas and their restrictions.
(iii) In order to protect certain TV/DTV stations and to ensure protection
from these stations which may have extremely large contours due to unusual
height situations, an additional distance factor must be used by all public
safety base, control and mobile stations. For all co-channel and adjacent
channel TV/DTV stations which have an HAAT between 350 and 600 meters,
public safety stations must add the following DISTANCE FACTOR to the value
obtained from the referenced Tables in Sec. 90.309 and to the distance for
control and mobile stations on adjacent TV/DTV channels (96.5 km).
DISTANCE FACTOR = (TV/DTV HAAT−350) ÷ 14 in kilometers, where HAAT is the TV
or DTV station antenna height above average terrain obtained from its
authorized or proposed facilities, whichever is greater.
(iv) For all co-channel and adjacent channel TV/DTV stations which have an
antenna height above average terrain greater than 600 meters, public safety
stations must add 18 kilometers as the DISTANCE FACTOR to the value obtained
from the referenced Tables in Sec. 90.309 and to the distance for control and
mobile stations on adjacent TV/DTV channels (96.5 km).
Note to Sec. 90.545: The 88.5 km (55.0 mi) Grade B service contour (64 dB µV/m)
is based on a hypothetical TV station operating at an effective radiated
power of one megawatt, a transmitting antenna height above average terrain
of 610 meters (2000 feet) and the Commission's R–6602 F(50,50) curves. See
Sec. 73.699 of this chapter. Maximum facilities for TV stations operating in the
UHF band are 5 megawatts effective radiated power at an antenna HAAT of 610
meters (2,000 feet). See Sec. 73.614 of this chapter. The equivalent contour for
DTV stations is based on a 41 dB µV/m signal strength and the distance to the
F(50,90) curve. See Sec. 73.625 of this chapter.
[ 63 FR 58651 , Nov. 2, 1998, as amended at 65 FR 53646 , Sept. 5, 2000; 69 FR 59536 , Oct. 4, 2004]
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