CONELRAD

CONELRAD (Control of Electromagnetic Radiation) was a planned method of emergency broadcasting to the public of the United States in the event of World War III. It served two purposes; to prevent Soviet bombers from homing in on American cities by using broadcasting stations as beacons, and to provide essential Civil Defense information. President Harry S Truman established CONELRAD in 1951.

All broadcast stations would monitor a designated stations in an area. In the event of an emergency, all United States television and FM radio stations were to leave the air. Mediumwave, or AM stations would broadcast on one of two frequencies, 640 kHz or 1240 kHz, at low power. Radio sets made after 1953 would have the frequencies marked by the triangle-in-circle symbol of Civil Defense.

It was succeeded by the Emergency Broadcast System in 1963 and the Emergency Alert System in 1997.

Fictional treatments of how CONELRAD would work can be found in the novel Alas, Babylon by Pat Frank, and the 1962 movie Panic in the Year Zero.