Throughout the 1950s and early 1960s there were numerous informational brochures issued to the public on the topic of the CONELRAD emergency broadcasting system. The unwieldy acronym stands for CONtrol of ELectromagnetic RADiation. CONELRAD existed from 1951 through 1963 when the Emergency Broadcasting System replaced it.
The following is how this 1953 iteration of the brochure explained the system to Americans:
The broadcasting industry and the government, working together, have devised a special system of AM (Standard) radio broadcasting to bring you official information in time of emergency. Of course, in 1999 "CONELRAD" was resurrected as the unwieldy name of a web site devoted to Cold War popular culture. Perhaps you have heard of it...
The system is officially entitled “Plan for CONtrol of ELtromagnetic RADiation”—CONELRAD for short.
Remember that name, CONELRAD. Remember what it means – “Tune your AM (Standard) radio to either 340 or 1240.”
Under the CONELRAD emergency broadcasting system, you will be able to receive radio programs from three different sources—local, State, and National. Programs originating locally will be broadcast direct. Line connections are arranged for programs originating on a State or regional basis. By using the existing network structures and line connections between stations, defense officials can broadcast programs which will reach the entire country…
Your television set and FM (frequency modulation) radio will go off the air in a civil defense emergency, because their broadcast beams could be used as direction finders by enemy bombers. Use your AM (Standard) radio…
If you are listening to any kind of radio or television set when the alert sounds, you will hear a message like this: “We interrupt our normal program to cooperate in security and civil defense measures as requested by the United States Government… This is a CONELRAD radio Alert… Listen carefully! This station is now leaving the air. During the CONELRAD radio Alert there will be no FM or TV programs. The only program on the air will be on your standard radio at 640 or 1240 kilocycles, starting in a few minutes. Tune your standard radio receiver to 340 or 1240 kilocycles for official instructions, news, and other information.”
If you are not listening to your radio or TV set when this announcement is made, when you hear civil defense sirens or attack warning signals, you will know that the CONELRAD system has gone into operation…
CONELRAD BROCHURE - 1953
By the U.S. Government Printing Office