§  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 39DEG15' N. on the north, 78DEG30'
   W. on the east, 37DEG30' N. on the south and 80DEG30' 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 40DEG07'50" N Latitude, 105DEG14'40" 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=120p 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/m^2 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/m^2 ) 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.

   (f) Protection to the Federal Government's receive earth station
   operations in the Denver, Colorado and Washington D.C. areas in the
   17,700 to 19,700 MHz band.

   (1) With the exception of applicants for a station authorization to
   operate within a 5 km radius of 39DEG40'23" N Lat. and 105DEG13'03" W
   Long (Morrison, CO), applicants will not be authorized to operate
   within a 50 km radius of 39DEG43'00" N Lat. and 104DEG46'00" W Long.
   (Denver, CO) and within a 50 km radius of 38DEG48'00" N Lat. and
   76DEG52'00" W Long. (Washington, DC).

   (2) To minimize or avoid harmful interference to Government Satellite
   Earth Stations located in the Denver, Colorado and Washington, DC
   areas, any application for a new station license for MVPD operations 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 areas
   defined by the following rectangles or circles:

   (i) A circular area within a 5 km radius of 39DEG40'23" N Lat. and
   105DEG13'03" W Long. (Morrison, CO)

   (ii) Within the rectangular areas defined as follows (vicinity of
   Denver, CO):

   Rectangle 1:

   41DEG30'00" N. Lat. on the north

   103DEG10'00" W. Long. on the east

   38DEG30'00" N. Lat. on the south

   106DEG30'00" W. Long. on the west

   Rectangle 2:

   38DEG30'00" N. Lat. on the north

   105DEG00'00" W. Long. on the east

   37DEG30'00" N. Lat. on the south

   105DEG50'00" W. Long. on the west

   Rectangle 3:

   40DEG08'00" N. Lat. on the north

   107DEG00'00" W. Long. on the east

   39DEG56'00" N. Lat. on the south

   107DEG15'00" W. Long. on the west

   (iii) Within the rectangle and circle areas as follows (vicinity of
   Washington, DC):

   Rectangle

   38DEG40'00" N. Lat. on the north

   78DEG50'00" W. Long. on the east

   38DEG10'00" N. Lat. on the south

   79DEG20'00" W. Long. on the west or

   or

   (iv) Within a radius of 178 km of 38DEG48'00" N. Lat. / 76DEG52'00" W.
   Long.

   Note to § 78.19: The coordinates cited in this section are specified in
   terms of the "North American Datum of 1983 (NAD 83)" with an accuracy
   of -30 meters with respect to the "National Spacial Reference System."

   [ 37 FR 3292 , Feb. 12, 1972]

   Editorial Note:   ForFederal Registercitations affecting § 78.19, see
   the List of CFR Sections Affected, which appears in the Finding Aids
   section of the printed volume and on GPO Access.