CONELRAD Logo, incorporating the shield of United States Civil Defense

CONELRAD (Control of Electromagnetic Radiation) was a method of emergency broadcasting to the public of the United States in the event of enemy attack during the Cold War. It was intended to serve two purposes; to prevent Soviet bombers from homing in on American cities by using radio or TV stations as beacons, and to provide essential civil defense information. U.S. President Harry S. Truman established CONELRAD in 1951. After the development of intercontinental ballistic missiles reduced the likelihood of a bomber attack, CONELRAD was replaced by the Emergency Broadcast System on August 5, 1963, which was later replaced with the Emergency Alert System in 1997; all were administered by the Federal Communications Commission (FCC).[1]

Unlike its successors, the EBS and EAS, CONELRAD was never intended to be used for severe weather warnings or local civil emergencies.



Prior to 1951, there was no method that the U.S. government could use to broadcast warnings to citizens in the event of an emergency. However, radio stations and networks could interrupt normal programming and issue a bulletin in the event of an emergency, as happened during the attack on Pearl Harbor on December 7, 1941, as well as the first successful tornado warning near Tinker Air Force Base in 1948. This type of broadcasting was the forerunner to CONELRAD.

"CD Mark" symbols like this (though generally shown as simple white triangles) were on every radio sold in the U.S., at the 640 kHz and 1240 kHz frequency points, to help listeners find the CONELRAD stations.

The CONELRAD concept was originally known as the Key Station System. According to an FCC document created during the "Informal Government - Industry Technical Conference" on March 26, 1951:

"The primary plan for alerting broadcast stations that is currently being considered by the FCC Study Group is known as the Key Station System. The arrangement requires certain telephone circuits (private wire or direct line to Toll Board) between the Air Defense Control Centers (A.D.C.C.) and specified radio stations to be known as "Basic Key Stations".
Additional telephone circuits (direct line to Toll Board) will be required in certain cases, between "Basic Key Stations" and other stations to be known as "Relay Key Stations". Each "Basic Key Station" receiving an alert or warning signal from the A.D.C.C. shall, if so directed, proceed to broadcast a predetermined message and also relay the message by telephone to all "Relay Key Stations" under his control as specified." CONELRAD was officially introduced on December 10, 1951.[2]

CONELRAD had a simple system for alerting the public and other "downstream" stations, consisting of a sequence of shutting the station off for five seconds, returning to the air for five seconds, again shutting down for five seconds, and then transmitting a tone for 15 seconds. Key stations would be alerted directly. All other broadcast stations would monitor a designated station in their area.

In the event of an emergency, all United States television and FM radio stations were required to stop broadcasting. Upon alert, most AM medium wave stations shut down. The stations that stayed on the air would transmit on either 640 or 1240 kHz. They would transmit for several minutes, and then go off the air and another station would take over on the same frequency in a "round robin" chain. This was to confuse enemy aircraft who might be navigating using Radio Direction Finding. By law, radio sets manufactured between 1953 and 1963 had these frequencies marked by the triangle-in-circle ("CD Mark") symbol of Civil Defense.[3]

Cold War era poster.

Although the system by which the CONELRAD process was initiated (switching the transmitter on and off) was simple, it was prone to numerous false alarms, especially during lightning storms. [4]Transmitters could also be damaged by the quick cycling. The switching later became known informally as the "EBS Stress Test" (due to many transmitters failing during tests) and was eventually discontinued when broadcast technology advanced enough to make it unnecessary.

Beginning January 2, 1957, U.S. amateur radio came under CONELRAD rules and all stations, while operating, were required to verify at least once every 10 minutes that a normal broadcast station was on the air. If not, the amateur operators were required to stop transmitting. Several companies marketed special receivers that would sound an alarm and automatically deactivate the amateur's transmitter when the monitored broadcast station went off the air.[5]

CONELRAD in pop culture

Fictional treatments of CONELRAD are found in the novel Alas, Babylon by Pat Frank, the 1962 movie Panic in Year Zero, the 1955 "Medic" TV episode entitled "Flash of Darkness", the 1961 Twilight Zone episode "The Shelter,", as well as the CBS television network's 1958 dramatized documentary A Day Called 'X'. The movie The Omega Man (1971) contains an anachronistic depiction of a CONELRAD transmission during a biological warfare attack ("CONELRAD channel! This is a Class 1 emergency! Stay in your homes!") - the attack is shown as taking place in 1975, 12 years after CONELRAD was discontinued. The 1954 TV film Atomic Attack! references tuning the dial to AM 640 or 1240.

There was a hardcore punk-rock band in Pittsburgh, Pennsylvania, named Conelrad.

Bob Dylan references the system in the song "Talkin' World War III Blues".

In 1967, Alabama rock band The Candymen (who had been Roy Orbison's back-up band) released their first LP, also named "The Candymen" which included a song about nuclear war called "Even the Grass Has Died". The third verse goes "The radio's on but oh, I'm feeling so sad. The music's been replaced by some cat they call Conelrad."

In his comedy album 200 M.P.H., Bill Cosby jokes about a father who falls asleep while watching TV. When the father's son tries to turn off the set, explaining that it is tuned to "Conelrad," the father protests, "Leave it alone—he's a hell of a detective!"

See also


  1. ^ "Sign-off for conelrad". Time. July 12, 1963.,9171,940303,00.html. Retrieved 2008-09-27. 
  2. ^ "City's Civil Defense Sirens Will Be Tested Tomorrow". New York Times: pp. 30. September 16, 1963. Retrieved 2008-09-27. 
  3. ^ Rhodes, Charles (September 17, 2008). "An Emergency Alert System for the Digital Era". TV Technology (New Bay Media): pp. 30–34. Retrieved 2008-09-27. 
  4. ^ Mishkind, Barry (22 March 1999). "Broadcast History". The Broadcast Archive. Retrieved 29 October 2009. 
  5. ^ The Radio Amateur's Handbook, American Radio Relay League. 1958 ed, p.143

External links

Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • CONELRAD — ☆ CONELRAD [kän′əl rad΄ ] n. [con(trol of) el(ectromagnetic) rad(iation)] a former system (from 1951 to 1963) of shifting broadcasting frequencies of AM stations to prevent possible use of their radio beams by enemy aircraft as a navigational aid …   English World dictionary

  • Conelrad (band) — Conelrad Origin Pittsburgh, Pennsylvania United States Genres metalcore, post hardcore[1] Years active 2001 – present Labels …   Wikipedia

  • Conelrad (disambiguation) — Conelrad may refer to: *Conelrad , the 1950 s civil defense program *Conelrad (band), a metal band …   Wikipedia

  • Conelrad — /kon l rad /, n. a system formerly used by the U.S. civil defense system to prevent enemy planes or missiles from homing on radio and television frequencies. [1955 60; con(trol of) el(ectromagnetic) rad(iation)] * * * …   Universalium

  • CONELRAD — Control of Electromagnetic Radiation ( > IEEE Standard Dictionary ) …   Acronyms

  • CONELRAD — Control of Electromagnetic Radiation ( > IEEE Standard Dictionary ) …   Acronyms von A bis Z

  • conelrad — con·el·rad …   English syllables

  • conelrad — ˈkänəlˌrad, ˌraa(ə)d noun ( s) Etymology: control of electromagnetic radiation : a system for preventing an enemy from using radio signals from any particular AM station as a guide for aircraft or missiles by shifting all AM stations to either of …   Useful english dictionary

  • Emergency Broadcast System — For the record label, see Emergency Broadcast System Records. For the multimedia group, see Emergency Broadcast Network. The Emergency Broadcast System (EBS) was an emergency warning system in the United States, used from 1963 to 1997, when it… …   Wikipedia

  • Sluts and Slobs — Infobox Album | Name = Sluts And Slobs Type = EP Artist = Conelrad Released = September 30, 2006 (U.S.) Genre = Metal Recorded = Epigram 154 Pittsburgh Label = Oh No Vertigo (U.S.)| Length = 7:45 | Producer = Conelrad Sluts and Slobs is a 5 song… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”