§ 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)(1) 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°15′ N. on the north, 78°30′ W. on
   the east, 37°30′ N. on the south and 80°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.

   (2) Any applicant for a new permanent base or fixed station
   authorization to be located on the islands of Puerto Rico, Desecheo,
   Mona, Vieques, and Culebra, or for a modification of an existing
   authorization which would change the frequency, power, antenna height,
   directivity, or location of a station on these islands and would
   increase the likelihood of the authorized facility causing
   interference, shall notify the Interference Office, Arecibo
   Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612, in writing or
   electronically, of the technical parameters of the proposal. Applicants
   may wish to consult interference guidelines, which will be provided by
   Cornell University. Applicants who choose to transmit information
   electronically should e-mail to: prcz@naic.edu.

   (i) The notification to the Interference Office, Arecibo Observatory
   shall be made prior to, or simultaneously with, the filing of the
   application with the Commission. The notification shall state the
   geographical coordinates of the transmit antenna (NAD-83 datum),
   antenna height above ground, ground elevation at the antenna, antenna
   directivity and gain, proposed frequency and FCC Rule Part, type of
   emission, effective isotropic radiated power, and whether the proposed
   use is itinerant. Generally, submission of the information in the
   technical portion of the FCC license application is adequate
   notification. In addition, the applicant shall indicate in its
   application to the Commission the date notification was made to the
   Arecibo Observatory.

   (ii) After receipt of such applications, the Commission will allow the
   Arecibo Observatory a period of 20 days for comments or objections in
   response to the notification indicated. The applicant will be required
   to make reasonable efforts in order to resolve or mitigate any
   potential interference problem with the Arecibo Observatory and to file
   either an amendment to the application or a modification application,
   as appropriate. If the Commission determines that an applicant has
   satisfied its responsibility to make reasonable efforts to protect the
   Observatory from interference, its application may be granted.

   (iii) The provisions of this paragraph do not apply to operations that
   transmit on frequencies above 15 GHz.

   (d) Protection for Table Mountain Radio Receiving Zone, Boulder County,
   Colorado: Applicants for a station authorization to operate in the
   vicinity 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°07′50″ N Latitude, 105°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:
   Frequency range         In authorized bandwidth of service
                   Field strength (mV/m) Power flux density^1 (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

   ^1Equivalent values of power flux density are caculated assuming free
   space characteristic impedance of 376.7 = 120Ï€ ohms.

   ^2Space 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 § 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.

   (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 the Public Safety and Homeland Security Bureau, Federal
   Communications Commission, Washington, DC 20554.

   (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.

   (f) 17.7-19.7 GHz band. The following exclusion areas and coordination
   areas are established to minimize or avoid harmful interference to
   Federal Government earth stations receiving in the 17.7-19.7 GHz band:

   (1) No application seeking authority to operate in the 17.7-19.7 GHz
   band will be accepted for filing if the proposed station is located
   within 50 km of Denver, CO (39°43′ N., 104°46′ W.) or Washington, DC
   (38°48′ N., 76°52′ W.).

   (2) Any application seeking authority for a new fixed station license
   supporting the operations of Multichannel Video Programming
   Distributors (MVPD) in the 17.7-17.8 GHz band or to operate in the
   17.8-19.7 GHz band for any service, or for modification of an existing
   station license in these bands which would change the frequency, power,
   emission, modulation, polarization, antenna height or directivity, or
   location of such a station, must be coordinated with the Federal
   Government by the Commission before an authorization will be issued, if
   the station or proposed station is located in whole or in part within
   any of the following areas:

   (i) Denver, CO area:

   (A) Between latitudes 41°30′ N. and 38°30′ N. and between longitudes
   103°10′ W. and 106°30′ W.

   (B) Between latitudes 38°30′ N. and 37°30′ N. and between longitudes
   105°00′ W. and 105°50′ W.

   (C) Between latitudes 40°08′ N. and 39°56′ N. and between longitudes
   107°00′ W. and 107°15′ W.

   (ii) Washington, DC area:

   (A) Between latitudes 38°40′ N. and 38°10′ N. and between longitudes
   78°50′ W. and 79°20′ W.

   (B) Within 178 km of 38°48′ N, 76°52′ W.

   (iii) San Miguel, CA area:

   (A) Between latitudes 34°39′ N. and 34°00′ N. and between longitudes
   118°52′ W. and 119°24′ W.

   (B) Within 200 km of 35°44′ N., 120°45′ W.

   (iv) Guam area: Within 100 km of 13°35′ N., 144°51′ E.

   Note to § 78.19(f): The coordinates cited in this section are specified
   in terms of the “North American Datum of 1983 (NAD 83).

   [ 37 FR 3292 , Feb. 12, 1972]

   Editorial Note: For Federal Register citations affecting § 78.19, see
   the List of CFR Sections Affected, which appears in the Finding Aids
   section of the printed volume and at www.govinfo.gov.

   return arrow Back to Top