keep the Germans thinking along those lines, the Allies set up a
entire army. The ruse worked so well that a large part of the German
tank force remained in the Calais area, rather than being used
against the Allies at Normandy.
Deception operations, which are
highly believable to an enemy, are likely to be more successful than
less believable deceptions.
(3) Another example of deception was the Japanese attack on
The Japanese Fleet sailed across the Pacific in
complete radio silence.
home islands simulated the fleet's normal radio activity.
location, intentions, and activities of the Japanese fleet.
(4) Code breaking was another major effort in this period.
successful example was Operation Magic (1937-1940), conducted by the
U.S. against the diplomatic codes of Japan.
This effort gave the
U.S. information about Japanese military and national intentions.
Later EW efforts against Japan led to the destruction of the Japanese
carrier fleet at Midway. In Europe, the British success in breaking
the German code system ULTRA allowed the Allies to read German high
command and naval traffic.
The success in defeating the submarine
threat to Allied convoys crossing the Atlantic can be attributed, in
part, to the breaking of the German codes.
(5) The development of radio detection and ranging (radar)
affected the outcome of World War II.
Radar was used for both the
early detection and location of aircraft and naval surface forces.
The development of systems and techniques to locate and identify
radar sets grew into separate activities.
They would eventually be
given the names electronic intelligence (ELINT) and electronic
Many years later, ELINT and ELSEC would play a
major roll in the Persian Gulf War of 1991.
c. Korean War. During the Korean War, EW was used by both United
Nations (UN) and North Korean forces. The Soviets supplied the North
Koreans with ground-based radars that were used against American
bombers. U.S. forces responded by jamming enemy radars with tin-foil
strips, called chaff.
(1) Both sides intercepted and analyzed radio signals.
were not as effective; however, they could locate UN positions
through the technique of direction finding (DF).