Goto Section: 90.543 | 90.547 | Table of Contents
FCC 90.545
Revised as of December 4, 2012
Goto Year:2011 |
2013
§ 90.545 TV/DTV interference protection criteria.
Public safety base, control, and mobile transmitters in the 769-775 MHz
and 799-805 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 dBµV/m) (88.5 kilometers or 55.0
miles) of the TV station or 17 dB at the equivalent Grade B contour (41
dBµV/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 dBµV/m) (88.5 kilometers or 55.0
miles) of the TV station or −23 dB at the equivalent Grade B contour
(41 dBµV/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 § 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 § § 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 § 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:
State City NTSC TV Ch. DTV Ch. ERP (kW) HAAT (m)
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
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 § 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 § 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 § 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 dBµV/m for TV and 41 dBµV/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 dBµV/m for TV and 41 dBµV/m coverage contour
for DTV stations) will be achieved. Directions for calculating powers,
heights, and reduction curves are listed in § 90.309 for land mobile
stations. Directions for calculating coverage contours are listed in
§ § 73.683-685 for TV stations and in § 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 § 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 § 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 § 90.309 and to the
distance for control and mobile stations on adjacent TV/DTV channels
(96.5 km).
Note to § 90.545: The 88.5 km (55.0 mi) Grade B service contour (64
dBµV/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 § 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
§ 73.614 of this chapter. The equivalent contour for DTV stations is
based on a 41 dBµV/m signal strength and the distance to the F(50,90)
curve. See § 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; 72 FR 67577 , Nov. 29, 2007]
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Goto Section: 90.543 | 90.547
Goto Year: 2011 |
2013
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