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 of Virginia and West Virginia, and also includes a sliver of Maryland. The NRQZ is centered between the Green Bank Observatory in Green Bank, West Virginia, and Sugar Grove Station in Sugar 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.
Most broadcast transmitters in the core of the Quiet Zone are forced to operate at reduced power and use highly directional antennas. This makes cable and satellite all but essential for acceptable television in much of the region. Restrictions on transmissions are tightest within ten miles (16 km) of the Green Bank and Sugar Grove facilities, where most omnidirectional and high-power transmissions are prohibited.
The most severe restrictions imposed on the general public are only in place within the 20-mile (32 km) radius of the Green Bank Observatory. The Observatory actively polices the area for devices emitting noticeably high amounts of electromagnetic radiation such as microwave ovens, Wi-Firouters and faulty electrical equipment and request citizens discontinue their usage. They possess no legal powers of enforcement (although the FCC can still impose a fine of $50 on violators), but will work with residents to find solutions.
“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 in Snowshoe Mountain Resort in nearby Snowshoe, West Virginia, one of the state’s major ski areas.”
The Green Bank Interference Protection Group maintains policies to manage radio-frequency interference (RFI) by dividing into five zones based on available legal instruments.
Zone 1 and zone 2 are located within the property of the Green Bank Observatory. The entire property is designed as zone 1 except small portions (such as housing, visitor and laboratory areas) that are designed as zone 2. Zone 1, also called Radio Astronomy Instrument Zone, restricts intentional radiators to only those are deemed essential. All unintentional radiators must be operated within the ITU-R RA.769 recommendations on protection criteria used for radio astronomical measurements. Gasoline-powered motor vehicles are forbidden within zone 1 as the ignition system on spark-ignited engines generates noticeable radio interference, resulting in all vehicles and equipment needing to be diesel-powered. Zone 2, also called Observatory Building Zone, allows intentional radiators licensed by 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, however digital cameras are prohibited, although filmphotography is allowed.
Zone 3 and zone 4 are governed by the Radio Astronomy Zoning Act which is the Chapter 37A of the West Virginia Code. It strictly regulates radio transmitters within 2 miles (3.2 km) and within 10 miles (16 km) of the Green Bank Observatory, respectively. Within these zones, interference to observations will be identified and documented. The owners of the offending equipment will be personally visited 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 in the Chapter 37A.
Zone 5 is the boundary of National Radio Quiet Zone; the National Radio Quiet Zone Administrator at the Green Bank Observatory manages the enforcement policies.
^Sizemore, Wes; Acree, Jeff. “The National Radio Quiet Zone”(PDF). NRAO. Retrieved July 14, 2016. 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.