§ 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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