Sec. 78.19 Interference.
(a) Applications for CARS stations shall endeavor to select an
assignable frequency or frequencies which will be least likely to result
in interference to other licensees in the same area since the FCC itself
does not undertake frequency coordination.
(b) Applicants for CARS stations shall take full advantage of all
known techniques, such as the geometric arrangement of transmitters and
receivers, the use of minimum power required to provide the needed
service, and the use of highly directive transmitting and receiving
antenna systems, to prevent interference to the reception of television
STL, television intercity relay, and other CARS stations.
(c) Radio Astronomy and Radio Research Installations. In order to
minimize harmful interference at the National Radio Astronomy
Observatory site located at Green Bank, Pocahontas County, W. Va., and
at the Naval Radio Research Observatory at Sugar Grove, Pendleton
County, W.Va., an applicant for authority to construct a CARS station,
except a CARS pickup station, or for authority to make changes in the
frequency, power, antenna height, or antenna directivity of an existing
station within the area bounded by 39 deg.15' N. on the north,
78 deg.30' W. on the east, 37 deg.30' N. on the south and 80 deg.30' W.
on the west shall, at the time of filing such application with the
Commission, simultaneously notify the Director, National Radio Astronomy
Observatory, Post Office Box No. 2, Green Bank, WV 24944, in writing, of
the technical particulars of the proposed station. Such notification
shall include the geographical coordinates of the antenna, antenna
height, antenna directivity if any, proposed frequency, type of
emission, and power. In addition, the applicant shall indicate in his
application to the Commission the date notification was made to the
Observatory. After receipt of such application, the Commission will
allow a period of 20 days for comments or objections in response to the
notifications indicated. If an objection to the proposed operation is
received during the 20-day period from the National Radio Astronomy
Observatory for itself or on behalf of the Naval Radio Research
Observatory, the Commission will consider all aspects of the problem and
take whatever action is deemed appropriate.
(d) Protection for Table Mountain Radio Receiving Zone, Boulder
County, Colorado: Applicants for a station authorization to operate in
the vicinity
[[Page 674]]
of Boulder County, Colorado under this part are advised to give due
consideration, prior to filing applications, to the need to protect the
Table Mountain Radio Receiving Zone from harmful interference. These are
the research laboratories of the Department of Commerce, Boulder County,
Colorado. To prevent degradation of the present ambient radio signal
level at the site, the Department of Commerce seeks to ensure that the
field strengths of any radiated signals (excluding reflected signals)
received on this 1800 acre site (in the vicinity of coordinates
40 deg.07'50''N Latitude, 105 deg.14'40''W Longitude) resulting from new
assignments (other than mobile stations) or from the modification or
relocation of existing facilities do not exceed the following values:
------------------------------------------------------------------------
In authorized bandwidth
of service
-------------------------
Frequency range Field Power flux
strength density \1\
(mV/m) (dBW/m\2\)
------------------------------------------------------------------------
Below 540 kHz................................. 10 -65.8
540 to 1600 kHz............................... 20 -59.8
1.6 to 470 MHz................................ 10 \2\ -65.8
470 to 890 MHz................................ 30 \2\ -56.2
Above 890 MHz................................. 1 \2\ -85.8
------------------------------------------------------------------------
\1\ Equivalent values of power flux density are caculated assuming free
space characteristic impedance of 376.7=120 ohms.
\2\ Space stations shall conform to the power flux density limits at the
earth's surface specified in appropriate parts of the FCC rules, but
in no case should exceed the above levels in any 4 kHz band for all
angles of arrival.
(1) Advance consultation is recomended particularly for those
applicants who have no reliable data which indicates whether the field
strength or power flux density figures in the above table would be
exceeded by their proposed radio facilities (except mobile stations). In
such instances, the following is a suggested guide for determining
whether coordination is recommended:
(i) All stations within 2.4 km (1.5 statute miles);
(ii) Stations within 4.8 km (3 statute miles) with 50 watts or more
effective radiated power (ERP) in the primary plane of polarization in
the azimuthal direction of the Table Mountain Radio Receiving Zone;
(iii) Stations within 16 km (10 statute miles) with 1 kW or more ERP
in the primary plane of polarization in the azimuthal direction of the
Table Mountain Radio Receiving Zone;
(iv) Stations within 80 km (50 statute miles) with 25 kW or more ERP
in the primary plane of polarization in the azimuthal direction of the
Table Mountain Radio Receiving Zone.
(2) Applicants concerned are urged to communicate with the Radio
Frequency Management Coordinator, Department of Commerce, Research
Support Services, NOAA R/E5X2, Boulder Laboratories, Boulder, CO 80303;
telephone (303) 497-6548, in advance of filing their applications with
the Commission.
(3) The Commission will not screen applications to determine whether
advance consultation has taken place. However, applicants are advised
that such consultation can avoid objections from the Department of
Commerce or proceedings to modify any authorization which may be granted
which, in fact, delivers a signal at the site in excess of the field
strength specified herein.
(e) Protection for Federal Communications Commission monitoring
stations:
(1) Applicants in the vicinity of an FCC monitoring station for a
radio station authorization to operate new transmitting facilities or
changed transmitting facilities which would increase the field strength
produced over the monitoring station over that previously authorized are
advised to give consideration, prior to filing applications, to the
possible need to protect the FCC stations from harmful interference.
Geographical coordinates of the facilities which require protection are
listed in Sec. 0.121(c) of the Commission's Rules. Applications for
stations (except mobile stations) which will produce on any frequency a
direct wave fundamental field strength of greater than 10 mV/m in the
authorized bandwidth of service (-65.8 dBW/m2 power flux
density assuming a free space characteristic impedance of 120 ohms) at
the referenced coordinates, may be examined to determine extent of
possible interference. Depending on the theoretical field strength value
and existing root-sum-square or other ambient radio field signal levels
at the indicated coordinates, a clause protecting the monitoring station
may be added to the station authorization.
[[Page 675]]
(2) In the event that calculated value of expected field exceeds 10
mV/m (-65.8 dBW/m2) at the reference coordinates, or if there
is any question whether field strength levels might exceed the threshold
value, advance consultation with the FCC to discuss any protection
necessary should be considered. Prospective applicants may communicate
with: Chief, Compliance and Information Bureau, Federal Communications
Commission, Washington, D.C. 20554, Telephone (202) 632-6980.
(3) Advance consultation is suggested particularly for those
applicants who have no reliable data which indicates whether the field
strength or power flux density figure indicated would be exceeded by
their proposed radio facilities (except mobile stations). In such
instances, the following is a suggested guide for determining whether an
applicant should coordinate:
(i) All stations within 2.4 kilometers (1.5 statute miles);
(ii) Stations within 4.8 kilometers (3 statute miles) with 50 watts
or more average effective radiated power (ERP) in the primary plane of
polarization in the azimuthal direction of the Monitoring Stations.
(iii) Stations within 16 kilometers (10 statute miles) with 1 kW or
more average ERP in the primary plane of polarization in the azimuthal
direction of the Monitoring Station;
(iv) Stations within 80 kilometers (50 statute miles) with 25 kW or
more average ERP in the primary plane of polarization in the azimuthal
direction of the Monitoring Station;
(4) Advance coordination for stations operating above 1000 MHz is
recommended only where the proposed station is in the vicinity of a
monitoring station designated as a satellite monitoring facility in
section 0.121(c) of the Commission's Rules and also meets the criteria
outlined in paragraphs (f) (2) and (3) of this section.
(5) The Commission will not screen applications to determine whether
advance consultation has taken place. However, applicants are advised
that such consultation can avoid objections from the Federal
Communications Commission or modification of any authorization which
will cause harmful interference.
[ 37 FR 3292 , Feb. 12, 1972, as amended at 37 FR 15926 , Aug. 8, 1972; 37 FR 26733 , Dec. 15, 1972; 38 FR 1920 , Jan. 19, 1973; 42 FR 33037 , June
29, 1977; 44 FR 77167 , Dec. 31, 1979; 45 FR 78694 , Nov. 26, 1980; 50 FR 32418 , Aug. 12, 1985; 50 FR 40863 , Oct. 7, 1985; 50 FR 45406 , Oct. 31,
1985; 58 FR 44952 , Aug. 25, 1993; 61 FR 8478 , Mar. 5, 1996]
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