NRQZ.

Believe it or not, The National Radio Quiet Zone is a 13,000 mile / 34,000 sq km zone located in West Virginia (in America) is wireless-free… therein the nation’s largest land-based object (the Robert C. Byrd Green Bank Telescope measuring 2.3 acres / 93,077 sq meters resides). Tracking interstellar activity requires ‘radio-silence’ including the banning of baby monitors, microwaves and wireless doorbells!