National Radio Quiet Zone
Fact Sheet
Revised February 1985
The National Radio Quiet Zone (NRQZ) was established with FCC rulemaking Docket No. 11745, dated November 19, 1958, and enclosed area of approximately 13,000 square miles of Virginia and West Virginia as shown on the map. The purpose of the NRQZ is to minimize possible harmful interference to the National Radio Astronomy Observatory (NRAO) at Green Bank, WV and the Navy's space receiving facility at Sugar Grove, WV. Applications for radio services within the NRQZ are reviewed for compliance with the criteria af the observatories, which are:
- The computed power density the transmitter produces at the Observatory reference antenna should not exceed:
- 1 x 10-8 W/m2 for frequencies below 54MHz;
- 1 x 10-12 W/m2 for frequencies from 54 to 108 MHz;
- 1 x 10-14 W/m2 for frequencies from 108 to 470 MHz;
- 1 x 10-17 W/m2 for frequencies from 470 to 1000 MHz;
- f2(GHz) x 10-17 W/m2 for frequencies (f) above 1 GHz;
- except CCIR-224 densities for the radio astronomy frequency bands plus narrow guard-bands.
All non-Federal-Government radio services are required to obtain an FCC license for each transmitter. For the radio services listed below, FCC rules require any applicant for new or modified fixed-station, simultaneously to filing, to notify:
Director (Interference Office)
National Radio Astronomy Observatory
P.O. Box 2
Green Bank, WV 24944
in writing of the technical parameters of the application. The FCC will then consider comments or objections from NRAO. NRAO prefers that the notice consist of a copy of the completed FCC application form (which contains most of the technical parameters) plus a cover letter which states:
- That it is a notice of FCC application, a copy of which is attached, and the date of filing.
- Antenna directivity(ies): type, gain, horizontal pattern and its orientation in azimuth, sufficient to determine the effective radiated power (ERP) toward Green Bank, WV and Sugar Grove, WV for each antenna, including any control station antenna and its coordinates.
A copy of the cover letter should be attached to the original application when it is sent to the FCC.
The applicable FCC Rules and Radio Services are:
- 5.69 ............ Experimental
- 21.113(a) ........ Domestic Public Fixed
- 22.113(a) ........ Public Mobile
- 23.20(b) ......... International Fixed Public
- 25.203(g) ........ Satellite Communications
- 73.1030(a) ....... Broadcast
- 74.12, 74,24(i)... Exp., Aux., & Special Broadcast
- 78.19(c) ......... Cable Television Relay
- 81.31(a) ......... On Land Maritime
- 81.37 ............ Aviation
- 90.177(a),(b) .... Private Land Mobile
- 94.25(f) ......... Private Operational Fixed Microwave
- 95.17(g) ......... General Mobile
- 97.85(f),97.87(d). Amateur (repeaters, beacons)
- 99.11(e) ......... Disaster Communications
Requests for information and for preliminary evaluation of proposed stations for the (ERP) limit toward Green Bank and Sugar Grove should be sent to the Interference Office at the NRAO address above. Preliminary proposals should be stated as such and should include:
- Name and address of proposer and future applicant.
- Radio Service.
- Frequency of each transmitter.
- Antenna location(s) in latitude and longitude to nearest second.
- Antenna site ground elevation(s) above mean sea level (AMSL).
- Antenna (radiation center) height(s) above ground level (AGL).
If an ERP limit is not acceptable to the applicant, NRAO will assist in finding a mutually acceptable alternative.