
TheNational Radio Quiet Zone (NRQZ) is a large area of land in theUnited States designated as aradio quiet zone, in whichradio transmissions are restricted by law to facilitatescientific research and the gathering ofmilitary intelligence. About half of the zone is located in theBlue Ridge Mountains of west-centralVirginia while the other half is in theAllegheny Mountains of east-centralWest Virginia; a small part of the zone is in the southernmost tip of theMaryland panhandle.
The Quiet Zone is an approximate rectangle of land, 107.0 miles (172.2 km) on the north edge, 109.6 miles (176.4 km) on the south edge and 120.9 miles (194.6 km) on the east and west edges, comprising approximately 13,000 square miles (34,000 km2; 8,300,000 acres). It straddles the borders ofVirginia andWest Virginia, and also includes a small part ofMaryland. The NRQZ is centered between theGreen Bank Observatory inGreen Bank, West Virginia, andSugar Grove Station inSugar Grove, West Virginia. It includes all land with latitudes between 37° 30' 0.4" N and 39° 15' 0.4" N, and longitudes between 78° 29' 59.0" W and 80° 29' 59.2" W.[1]


Mostbroadcast transmitters in the central area of the Quiet Zone are required to operate at reduced power and use directional antennas. This makescable andsatellite essential for acceptable television in much of the region. Restrictions of transmissions are strictest within ten miles (16 km) of the Green Bank and Sugar Grove facilities,[4] where most omnidirectional and high-power transmissions are prohibited.
Not all radio transmissions are prohibited in the Quiet Zone. For example,emergency service (police, fire, and ambulance) radios andCB radios are permitted. However, owners of high-power transmitters, including television stations in theHarrisonburg–Staunton andCharlottesville markets, must coordinate their operations with the Green Bank Observatory. The only broadcast radio stations in the core of the Quiet Zone are part of theAllegheny Mountain Radio network, with onedaytimer AM station inFrost, West Virginia, ten miles from the observatory, and low-powered FM stations inMonterey, Virginia andMarlinton, West Virginia. Exceptions to restrictions are usually determined case by case, with preference given topublic safety concerns, such as for remote alarm systems,repeaters for emergency services, andNOAA Weather Radio.
The most severe restrictions to the general public are imposed within a 20-mile (32 km) radius of the Green Bank Observatory.[5] The Observatory polices the area actively for devices emitting excessiveelectromagnetic radiation such asmicrowave ovens,Wi-Fiaccess points, and faulty electrical equipment and asks people to stop using such equipment. It does not have enforcement power[6] (although the FCC can impose a fine of $50 on violators[7]) but will work with residents to find solutions.[8][9]
Cellular telephone use in the central area of the zone is also very restricted.[5]
"In Green Bank, though, the rules are even stronger, so much that some residents who are in direct sight of the radio telescope receivers, can't use Wi-Fi devices and even microwave ovens in all Green Bank Radio Astronomy housing units.Directional cellphone service areas are very limited, such as inSnowshoe Mountain Resort in nearbySnowshoe, West Virginia, one of the state's majorski areas."[10]
However, the observatory has pulled back on Quiet Zone enforcement, and locals have increasingly embraced the usage of microwave ovens, cellphones, and WiFi.[11]
The Green Bank resident and high school teacher had a microwave. She had a smartphone. She had Wi-Fi. She knew where to get a cell phone signal. "It's not like we're living some bohemian lifestyle," she told me. Such was hardly a secret. A house across the street from the observatory had Wi-Fi with the network name "Screw you NRAO," an unsubtle middle finger to the observatory's calls for quiet. Green Bank’s health clinic had Wi-Fi. So did the senior center. "We're not supposed to," said John Simmons, the county's director of senior programs and a former county commissioner, "But I think all that stuff about the noise levels is fabricated."
In 2019, the Green Bank Interference Protection Group was picking up about 175 hotspots within two miles of the observatory.[12]

The Green Bank Interference Protection Group maintains policies to manageradio-frequency interference (RFI) by dividing into five zones based on available legal instruments.[13][14] The National Radio Quiet Zone Administrator at the Green Bank Observatory manages the enforcement policies.
Zones 1 and Zone 2 are located within the property of the Green Bank Observatory. The entire property is designatedZone 1 except small portions (such as housing, visitor, and laboratory areas) that are designatedZone 2. Zone 1, theRadio Astronomy Instrument Zone, restrictsintentional radiators to those that are deemed essential. Allunintentional radiators must be operated within theITU-R RA.769 recommendations on protection criteria used for radio astronomical measurements. Gasoline-powered motor vehicles are prohibited in Zone 1 as theirspark-ignition engines generate significant radio interference, resulting in the requirement that all vehicles and equipment bediesel-powered.[15] Zone 2, theObservatory Building Zone, allows intentional radiators licensed by the National Radio Quiet Zone but not other radiators such as Wi-Fi,cordless phones, and other wireless equipment. Certain types of unintentional radiators are allowed.Digital cameras are prohibited, althoughfilm photography is allowed.[16]
Zone 3 and Zone 4 are governed by the Radio Astronomy Zoning Act, Chapter 37A of the West Virginia Code. It strictly regulates radio transmitters within ten miles (16 km) of the Green Bank Observatory. Zone 3, the area within two miles (3.2 km), has the greatest restriction; it is surrounded by Zone 4, in which progressively greater emissions are allowed at greater distances.[4] Within these zones, interference to observations are identified and documented. The owners of the offending equipment are visited personally to request cooperation in eliminating the interference. Enforcement is used as a last resort. Enforcement in Zone 4 may be more lenient than the limit set by Chapter 37A.
Zone 5 is the outermost part of the National Radio Quiet Zone.
TheFederal Communications Commission (FCC) created the Quiet Zone in 1958 to protect theradio telescopes at Green Bank and Sugar Grove from harmful interference.[17] Today, the Green Bank Observatory oversees the Quiet Zone.
The Quiet Zone also protects the antennas and receivers of theNavy Information Operations Command (NIOC) at Sugar Grove. The NIOC is the location of electronic intelligence-gathering systems and is today said to be a key station in theECHELON system operated by theNational Security Agency (NSA).[18]
The area has also attracted people who believe they suffer fromelectromagnetic hypersensitivity,[16][19][20] though scientific experiments have shown this condition is caused by thenocebo effect rather than electromagnetic waves.[21][22][23]
Clarksburg,Sutton (both in West Virginia), andLynchburg, Virginia, are just outside the Quiet Zone.
To keep the zone protected from signals that could confuse the telescope, Niday and others from the NRAO drive the 20-mile radius around the Green Bank Telescope weekly, policing for possible interference.
NRAO operates the National Radio Quiet Zone at Green Bank. We briefly outline its salient characteristics, and our experience with its day to day operation.
Interception Capabilities 2000 Report to the Director General for Research of the European Parliament (Scientific and Technical Options Assessment programme office) on the development of surveillance technology and risk of abuse of economic information.
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