§ 73.1030   Notifications concerning interference to radio astronomy, research
and receiving installations.

   (a)(1) Radio astronomy and radio research installations. In order to
   minimize harmful interference at the National Radio Astronomy
   Observatory site located at Green, Pocahontas County, West Virginia,
   and at the Naval Radio Research Observatory at Sugar Grove, Pendleton
   County, West Virginia, a licensee proposing to operate a short-term
   broadcast auxiliary station pursuant to § 74.24, and any applicant for
   authority to construct a new broadcast 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 notify the Interference Office, National Radio
   Astronomy Observatory, P.O. Box 2, Green Bank, West Virginia 24944.
   Telephone: (304) 456-2011. The notification shall be in writing and set
   forth the particulars of the proposed station, including the
   geographical coordinates of the antenna, antenna height, antenna
   directivity if any, proposed frequency, type of emission and power. The
   notification shall be made prior to, or simultaneously with, the filing
   of the application with the Commission. After receipt of such
   applications, the FCC 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 FCC 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 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, and
   effective radiated power.

   (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 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. The Commission shall determine whether an applicant has
   satisfied its responsibility to make reasonable efforts to protect the
   Observatory from interference.

   (b) Radio receiving installations. 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 (within the area bounded by 40°09′10″ N Latitude on the
   north, 105°13′31″ W Longitude on the east, 40°07′05″ N Latitude on the
   south, and 105°15′13″ W Longitude on the west) resulting from new
   assignments (other than mobile stations) or from the modification of
   relocation of existing facilities do not exceed the following values:
   Frequency range Field strength in authorized bandwidth of service
   (mV/m) Power flux density in authorized bandwidth of service
   (dBW/m^2)  ^1
   Below 540 kHz 10 −65.8
   540 to 1700 kHz 20 −59.8
   1.7 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 calculated 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 recommended 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 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 Table
   Mountain Receiving Zone;

   (iv) Stations within 80 km (50 statute miles) with 25 kW or more ERP in
   the primary plane polarization in the azimuthal direction of Table
   Mountain 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 objectimns 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.

   (c) Protection for Federal Communications Commission monitoring
   stations. (1) Applicants in the vicinity of a 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 in excess of 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 FCC 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 π
   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.

   (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
   § 0.121(c) of the Commission's Rules and also meets the criteria
   outlined in paragraphs (b) (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.

   [ 43 FR 32782 , July 28, 1978, as amended at  44 FR 77167 , Dec. 31, 1979;
    47 FR 9221 , Mar. 4, 1982;  50 FR 39003 , Sept. 26, 1985;  52 FR 25867 ,
   July 9, 1987;  52 FR 36879 , Oct. 1, 1987;  52 FR 37789 , Oct. 9, 1987;  56 FR 64872 , Dec. 12, 1991;  61 FR 8477 , Mar. 5, 1996;  62 FR 55532 , Oct.
   27, 1997;  63 FR 70048 , Dec. 18, 1998;  70 FR 31373 , June 1, 2005;  80 FR 53750 , Sept. 8, 2015]

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