CONELRAD
Author:
Tom
Sanders
When the United States and
the Soviet Union, allies during World War II, became
enemies in the Fifties, the possibility of Soviet warplanes
attacking the American mainland became real.
America's leaders also
realized that signals from domestic AM radio stations would
help approaching bombers find U.S. cities. On a portable
radio, a distant AM station's signal becomes stronger when the
radio is turned in one direction. An enemy navigator could
thus tune to 770, for example, turn his plane until the
station he heard was the strongest, and fly in that direction
to New York City.
In 1951, President Harry S
Truman signed legislation authorizing CONELRAD to begin
operation.
CONELRAD - CONtrol of
ELectronic RADiation - required all AM stations in the United
States to sign off in the event of an enemy attack, save for
those designated to stay on the air at either 640 or 1240.
Multiple signals on the same frequency, coming from different
directions, would prevent enemy planes from using one station
as a direction finder.
Manufacturers of radios were
required to mark the CONELRAD frequencies on all sets sold
in the United States. Many of these radios survive and are in
daily use today. The marking can be a triangle inside a circle
-- a variation on the Civil Defense logo -- just a triangle, a
dot, or the letters "CD," depending on the size of the radio.
I don't know why these two
frequencies were chosen. Possible reasons might include
the fact that they're an easy pair of numbers to remember,
and at opposite ends of the AM broadcast band, making the
markings on radio dials more visible.
Radios in those cool Fifties
cars, then, display this additional reminder of life
during the Cold War.
Stations were required to
test the system once a week. They'd sign off, come back on
with a tone, and explain that it was only a test. Once a year,
every station except those designated to move to 640 or 1240
went silent for a half hour. I remember hearing the last
national "Operation Alert" in 1961. It was strange to hear
nothing on the radio except one station where the announcers
were casually talking about why everyone else was off the air,
while reminding everyone to be thankful it wasn't the real
thing.
Intercontinental ballistic
missiles (ICBMs), armed with nuclear warheads and remote
controlled, with no need for AM radio signals, made CONELRAD
obsolete. The 640-1240 plan was replaced in 1963 with one that
allowed stations to broadcast emergency information while
remaining on their assigned frequencies.
CONELRAD lives, though; in the memories of Cold War
kids like me who were raised on radio, and in the collections
of radio buffs who look for sets with dials that have those
little triangles.
Tom Sanders
is a novelist and radio historian from Lexington, Michigan.
Tom Sanders
/ KC8YBX (ham radio call sign)
