We have only the vaguest idea where the broadcasts are coming from, and even less idea where they’re going. The sounds are strange—the synthesized voices of women and children mixed with snatches of music, Morse code, or high-pitched buzzing. Sometimes the transmissions appear on a fixed schedule, other times in short random bursts. The only thing they have in common is the eerie recitation of numbers, beamed through shortwave radio signals bouncing across the globe.
These are the “number stations,” which have mesmerized conspiracy theorists, radio enthusiasts, musicians and less obsessive members of the public for decades. They’ve been tracked with their own journal, recorded in an influential 4-CD set, and made appearances in lawsuits as well as a Cameron Crowe movie. No government agency has ever explained why they’ve taken over large portions of the shortwave radio dial, and why they’ve done so for years.
Read the rest of this fascinating article via The World’s Strangest Radio Broadcasts | Mental Floss.