In 1935 Robert Watson-Watt
wrote a paper entitled The Detection of
Aircraft by Radio Methods. This was presented to Henry
Tizard, the chairman of the Committee for the Scientific Survey
of Air Defence. Tizard was impressed with the idea and on 26th February
1935, Watson-Watt demonstrated his ideas at Daventry. As a result
he was appointed head of the Bawdsey Research Station in Felixstowe.
Watson-Watt's was based
on the idea of bouncing a radio wave against an object and measuring
its travel to provide targeting information. It was called radar
(radio detection and ranging).
By the outbreak of the
Second World War in September 1939, Watson-Watt had designed and
installed a chain of radar stations along the East and South coast
of England. During the Battle of Britain these stations were able
to detect enemy aircraft at any time of day and in any weather conditions.
Radar was also used by
ships and aircraft during the war. Germany was using radar by 1940
but Japan never used it effectively. The United States had a good
radar system and it was able to predict the attack on Pearl Harbor
an hour before it happened.
Britain tended to have
the best radar system during the early stages of the war and in
1940 the invention of the Magnetron cavity resonator enabled more
centimetric waves to be transmitted. It also enabled more compact
high-frequency sets to be used by aircraft in the Royal Air Force.
In 1941 the Royal Navy
began employing the ASV-3 radar system that helped them locate and
attack U-Boats. In December 1942, the RAF began using the Oboe navigational
system. A control station in Britain broadcast a radar beam in the
direction of the target, and another beam tracked an Oboe-equipped
Pathfinder bomber. A person in the control station could then guide
the aircraft directly to the target.
