Sec. 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 Sec. 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[deg]15[min] N on the north, 78[deg]30[min] W on the east, 
37[deg]30[min] N on the south, and 80[deg]30[min] 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 to change the frequency, power, antenna height, 
directivity, or location of a station on these islands shall notify the 
Interference Office, Arecibo Observatory, Post Office Box 995, Arecibo, 
Puerto Rico 00613, in writing or electronically, of the technical 
parameters of the proposal. Applicants shall 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

[[Page 286]]

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[deg]09[min]10[sec] N Latitude 
on the north, 105[deg]13[min]31[sec] W Longitude on the east, 
40[deg]07[min]05[sec] N Latitude on the south, and 
105[deg]15[min]13[sec] 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:

------------------------------------------------------------------------
                                                              Power flux
                                                   Field      density in
                                                strength in   authorized
                Frequency range                  authorized   bandwidth
                                                 bandwidth    of service
                                                 of service   (dBW/m\2\)
                                                   (mV/m)        \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 Sec. 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/m\2\ power 
flux density assuming a free space characteristic impedance of 120 [pi] 
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

[[Page 287]]

protection necessary should be considered. Prospective applicants may 
communicate with: Chief, Compliance and Information Bureau, Federal 
Communications Commission, Washington, DC 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 
Sec. 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]