CONTROL OF ELECTROMAGNETIC RADIATIONS (CONELRAD): United States. 1951. The CONELRAD system was designed to provide emergency communications to the general public in the event of a nuclear attack, while minimizing the potential for enemy strategic bomber aircraft to use radio stations for navigation purposes.  Under the CONELRAD operational concept, television and frequency modulated (FM) radio stations would cease broadcasting; selected amplitude modulated (AM) radio stations would broadcast emergency information on either 640 or 1240 kilocycles.  Activated by the Truman Administration in 1951, CONELRAD was replaced in 1963 by the Emergency Broadcast System.

After 1953 all radios sold in the United States were required to have two CD Marks, or triangles, on their frequency dials to assist radio listeners in locating the two CONELRAD frequencies.

To increase the survivability of this service, the Office of Civil Defense established a program to construct fallout shelters in selected stations to permit continued operations under fallout.

Sources: United States Department of Defense, Office of Civil Defense, Personal and Family Survival, Civil Defense Adult Education Course Student Manual, SM 3-11, Washington, District of Columbia, United States of America, U. S. Government Printing Office, 1963. Federation of American Scientists, "Control of Electronic Radiation CONELRAD," http://www.fas.org/nuke/guide/usa/c3i/conelrad.htm, 29 April 1998.

Entry 04119 - posted 25 November 2004