National Radio Quiet Zone

The National Radio Quiet Zone is a federally established area intended to protect highly sensitive radio-receiving equipment from radio-frequency interference. It encompasses about 13,000 square miles around Green Bank and Sugar Grove, West Virginia, where radio astronomy facilities and U.S. Navy receiving equipment operate. Limiting interference helps these instruments detect faint signals that could otherwise be obscured by transmissions from nearby equipment.

Created through Federal Communications Commission action in 1958 and a separate Interdepartment Radio Advisory Committee decision that same year, the zone has boundaries defined by specific latitude and longitude lines near the Virginia-West Virginia border. Within it, coordination is required for new or modified permanent, fixed, licensed transmitters. Operators are also strongly encouraged to consult the zone’s coordination office about frequency assignments that do not formally require coordination. The rules therefore combine mandatory review for specified transmitters with voluntary cooperation for other assignments, supporting the zone’s protective purpose. The Green Bank Observatory directs those seeking current coordination procedures to the National Radio Astronomy Observatory’s dedicated zone information.