Sec. 22.369  Quiet zones.

    Quiet zones are those areas where it is necessary to restrict 
radiation so as to minimize possible impact on the operations of radio 
astronomy or other facilities that are highly sensitive to interference. 
The areas involved and procedures required are as follows:
    (a) NRAO, NRRO. The requirements of this paragraph are intended to 
minimize possible interference at the National Radio Astronomy 
Observatory site located at Green Bank, Pocahontas County, West 
Virginia, and at the Naval Radio Research Observatory site at Sugar 
Grove, Pendleton County, West Virginia.
    (1) Carriers planning to construct and operate a new or modified 
Public Mobile Services station at a permanent fixed location within the 
area bounded by N.39 deg.15prime; on the north, W.78 deg.30prime; on the 
east, N.37 deg.30prime; on the south, and W.80 deg.30prime; on the west 
must notify the Director, National Radio Astronomy Observatory, Post 
Office Box No. 2, Green Bank, West Virginia 24944, in writing, of the 
technical details of the proposed operation. The notification must 
include the geographical coordinates of the antenna location, the 
antenna height, antenna directivity (if any), the channel, the emission 
type and power.
    (2) When an application for authority to operate a station is filed 
with the FCC, the notification required in paragraph (a)(1) of this 
section should be sent at the same time. The application must state the 
date that notification in accordance with paragraph (a)(1) of this 
section was made. After receipt of such applications, the FCC will allow 
a period of 20 days for comments or objections in response to the 
notifications indicated.
    (3) If an objection 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, after consideration of 
the record, take whatever action is deemed appropriate.
    (b) Table Mountain. The requirements of this paragraph are intended 
to minimize possible interference at the Table Mountain Radio Receiving 
Zone of the Research Laboratories of the Department of Commerce located 
in Boulder County, Colorado.
    (1) Carriers planning to construct and operate a new or modified 
Public Mobile Services station at a permanent fixed location in the 
vicinity of Boulder County, Colorado are advised to give consideration, 
prior to filing applications, to the need to protect the Table Mountain 
Radio Receiving Zone from interference. 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 deg.07prime;50Prime; North Latitude, 
105 deg.14prime;40Prime; West Longitude) resulting from new assignments 
(other than mobile stations) or from the modification or relocation of 
existing facilities do not exceed the values given in Table C-3 of this 
section.

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          Table C-3.--Field Strength Limits for Table Mountain          
------------------------------------------------------------------------
       Frequency range           Field strength      Power flux density 
------------------------------------------------------------------------
1.6 to 470 MHz..............  10 mV/m.............  -65.8 dBW/m2        
470 to 890 MHz..............  30 mV/m.............  -56.2 dBW/m2        
890 to 3000 MHz.............  1 mV/m..............  -85.8 dBW/m2        
------------------------------------------------------------------------
Note: Equivalent values of power flux density are calculated assuming   
  free space characteristic impedance of 376.7  (120).                                                        

    (2) Advance consultation is recommended, particularly for applicants 
that have no reliable data to indicate whether the field strength or 
power flux density figures in the above table would be exceeded by their 
proposed radio facilities. In general, coordination is recommended for:
    (i) Stations located within 2.4 kilometers (1.5 miles);
    (ii) Stations located within 4.8 kilometers (3 miles) transmitting 
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 located with 16 kilometers (10 miles) transmitting 
with 1 kW or more ERP in the primary plane of polarization in the 
azimuthal direction of Table Mountain Radio Receiving Zone;
    (iv) Stations located within 80 kilometers (50 miles) transmitting 
with 25 kW or more ERP in the primary plane of polarization in the 
azimuthal direction of Table Mountain Receiving Zone.
    (3) Applicants concerned are urged to communicate with the Radio 
Frequency Management Coordinator, Department of Commerce, Research 
Support Services NOAAR/E5X2, Boulder Laboratories, Boulder, CO 80303; 
telephone (303) 497-6548, in advance of filing their applications with 
the FCC.
    (4) The FCC will not screen applications to determine whether 
advance consultation has taken place. However, such consultation may 
avoid the filing of objections from the Department of Commerce or 
institution of proceedings to modify the authorizations of stations that 
radiate signals with a field strength or power flux density at the site 
in excess of those specified herein.
    (c) Federal Communications Commission protected field offices. The 
requirements of this paragraph are intended to minimize possible 
interference to FCC monitoring activities.
    (1) Carriers planning to construct and operate a new or modified 
Public Mobile Services station at a permanent fixed location in the 
vicinity of an FCC protected field office are advised to give 
consideration, prior to filing applications, to the need to avoid 
interfering with the monitoring activities of that office. FCC protected 
field offices are listed in Sec. 0.121 of this chapter.
    (2) Applications for stations (except mobile stations) that could 
produce on any channel a direct wave fundamental field strength of 
greater than 10 mV/m (-65.8 dBW/m\2\ power flux density assuming a free 
space characteristic impedance of 120 ) in the 
authorized bandwidth at the protected field office may be examined to 
determine the potential for interference with monitoring activities. 
After consideration of the effects of the predicted field strength of 
the proposed station, including the cumulative effects of the signal 
from the proposed station with other ambient radio field strength levels 
at the protected field office, the FCC may add a condition restricting 
radiation toward the protected field office to the station 
authorization.
    (3) In the event that the calculated field strength exceeds 10 mV/m 
at the protected field office site, or if there is any question whether 
field strength levels might exceed that level, advance consultation with 
the FCC to discuss possible measures to avoid interference to monitoring 
activities should be considered. Prospective applicants may communicate 
with: Chief, Compliance and Information Bureau, Federal Communications 
Commission, Washington, DC 20554.
    (4) Advance consultation is recommended for applicants that have no 
reliable data to indicate whether the field strength or power flux 
density figure indicated would be exceeded by

[[Page 136]]

their proposed radio facilities. In general, coordination is recommended 
for:
    (i) Stations located within 2.4 kilometers (1.5 miles);
    (ii) Stations located within 4.8 kilometers (3 miles) with 50 watts 
or more average effective radiated power (ERP) in the primary plane of 
polarization in the azimuthal direction of the protected field offices.
    (iii) Stations located within 16 kilometers (10 miles) with 1 kW or 
more average ERP in the primary plane of polarization in the azimuthal 
direction of the protected field office;
    (iv) Stations located within 80 kilometers (50 miles) with 25 kW or 
more average ERP in the primary plane of polarization in the azimuthal 
direction of the protected field office;
    (5) Advance coordination for stations transmitting on channels above 
1000 MHz is recommended only if the proposed station is in the vicinity 
of a protected field office designated as a satellite monitoring 
facility in Sec. 0.121 of this chapter.
    (6) The FCC will not screen applications to determine whether 
advance consultation has taken place. However, such consultation may 
serve to avoid the need for later modification of the authorizations of 
stations that interfere with monitoring activities at protected field 
offices.
[ 59 FR 59507 , Nov. 17, 1994, as amended at  61 FR 8477 , Mar. 5, 1996;  61 FR 54099 , Oct. 17, 1996]