The Emergency Broadcast System (EBS) was an emergency warning system in the USA used from 1963 to 1997, at which time it was replaced with the Emergency Alert System.
Purpose
The EBS was initiated in 1963 at the height of the civil defense era, to allow the president to address the entire nation in an emergency. EBS replaced the CONELRAD system that was instituted in 1951. The EBS was later further expanded through an interagency effort with the FCC, and the National Weather Service (NWS), to permit the system to be used for state and local emergencies. EBS was replaced by the Emergency Alert System (EAS) in 1997.
The system was never used for a nuclear emergency, though it was activated more than 20,000 times between 1976 and 1996 to broadcast civil emergency messages and warnings of severe weather hazards.
Until the system was superseded, radio and television stations were required to perform the Weekly Transmission Test Of The Attention Signal and Test Script a minimum of once a week at random days and times between 8:30 A.M and local sunset, unless during the test week, they have activated the EBS for a state or local emergency or participated in a coordinated State or local EBS test.
Test procedure
1) Normal programming is suspended.
2) The announcement written below is transmitted. "This is a test. For the next sixty seconds, this station will conduct a test of the Emergency Broadcast System (or Emergency Action Notification System). This is only a test." -or- "...(name of host station in a particular market) is conducting a test of the Emergency Broadcast System. This is only a test." -or- "...This station is conducting a test of the Emergency Broadcast System. This is only a test."
3) The special attention signal is sent. Broadcast the two-tone Attention signal (853 Hz + 960 Hz) from the EBS encoder for 20 to 25 seconds.
4) The announcement written below (depending on the variation) is transmitted. The first part reads: "This is a test of the Emergency Broadcast System (or Emergency Action Notification System). The broadcasters of your area in voluntary cooperation with the FCC and other authorities (or, in later years, Federal, State and local authorities) have developed this system to keep you informed in the event of an emergency."
Variations of the second half of the statement go as follows: One version went, "...If this had been an actual emergency, you would have been instructed to tune to one of the broadcast stations in your area..." Another version went, "...if this had been an actual emergency, you would have been instructed where to tune in your area for news and official information". Later versions went, "...the Attention Signal you just heard would have been followed by official information, news or instructions.". The final section of the second half had these variations: "(sponsoring station in a particular market) serves the (name of operational area) area. This concludes this test of the Emergency Broadcast System.", or on non-sponsoring stations, "This station serves the (name of operational area) area. This concludes this test of the Emergency Broadcast System (or Emergency Action Notification System)."
These variations were heard in different parts of the country throughout the years. At least one version made explicit reference to an attack on the United States as being a possible scenario for EBS activation. The announcement text was mandated by the FCC, including the "voluntary cooperation" clause, which was deceiving, as broadcast outlets were required by law to participate.
The purpose of the test was to allow the proper functioning of EBS tone transmitters and decoders to be verified. In addition to the weekly test, test activations of the entire system were conducted periodically for some years before being discontinued. These tests showed that about 80% of broadcast outlets nationwide would carry emergency programming within a period of five minutes when the system was activated.
The weekly broadcast of the EBS test message made it part of the U.S. cultural fabric of the era.
Network construction
The EBS was designed in a hierarchical system, with a relative handful of "Primary" stations that had direct communications with the White House and regional authorities. These stations would originate emergency programming, and other stations would monitor the primary stations for EBS messages to rebroadcast. In a few areas, "primary relay" stations were designated that served as relay points between primary stations and other stations that were unable to receive a primary station's broadcast.
Activation procedure
Actual activations originated with a primary station, which would transmit the test tone. Decoders at relay stations would activate, alerting the station operator to the need for activation. Then each relay station would broadcast the alert tone and then commence rebroadcasting programming from the primary station.
To prevent inadvertent activations and abuse, a ten bell alarm would be transmitted by the AP and UPI wire services along with a confirmation password during nationwide activations. Stations who subscribed to one of the wire services were not required to activate EBS if the teletype was operating but did not have a confirmation.
Despite these safeguards, the system was accidentally activated at 9:33 AM EST on February 20, 1971. A system operator accidentally "played the wrong tape" during a test of the system. As a result, an EBS activation message authenticated with the codeword "HATEFULNESS" was sent through the entire system, ordering stations to shut down and broadcast the alert of a national emergency. A cancellation message was not sent until 9:59 AM EST. This false alarm, in addition to creating great anxiety, showed great flaws in the EBS system. Many stations had not received the alert at all, and the vast majority of those that did ignored it. Numerous investigations were launched, but few changes were made to the EBS.