Full name: Robert Watson Watt Born: 13th April 1935 Invention/Achievement: Radar Date of introduction/Achievement: 2nd April 1935, Watson-Watt awarded patent for device for detecting and locating aircraft. Chain Home defence network established 1937-39. Died: 5th December 1973

The principles of radar (an acronym applied in 1940 by the United States Navy - Radio Detection and Ranging) have been known for many years.  In the 1930s several countries were working on radar systems.  However, its systematic development and application as part of an integrated defence system owes much to the work of the team led by Robert Watson-Watt in Britain from 1936.  

Watson-Watt was born in Scotland in 1892, a descendant of the engineer and inventor of the steam engine, James Watt.  In 1916 he joined the Meteorological Office, where he used radio waves in storm location through detecting the emissions of lightning.  

In 1924 he moved to the National Physical Laboratory, where the use of the Adcocks antenna and the WE-224 oscilloscope greatly improved the accuracy of his detection work, and In 1927 the Radio Research Establishment was formed with Watson-Watt as its director.  

In 1935 Watson-Watt was commissioned to investigate reports of a German radio based "death ray".  He demonstrated that such a device was unfeasible, but also mentioned that radio waves could be used to detect aircraft.  Watson-Watt sent a secret memo to the Air Ministry "Detection and location of aircraft by radio methods".

 A detection system was set up and demonstrated successfully and on 2^nd April 1935, Watson-Watt received a patent for a radio device for detecting and locating aircraft.  

From 1937-39 the Chain Home integrated network of aircraft detection systems was established and played a vital role in aerial defence during the Battle of Britain.  Radar equipment was still bulky and power hungry, but the invention in 1940 of the Magnetron cavity resonator enabled more accurate centimetric wavelengths to be transmitted.  It also reduced the size of radar equipment, allowing it to be fitted in aircraft.  

Watson-Watt was knighted in 1942 and after the war spent time in the USA.  Many years later in Canada he was caught speeding by a hand-held radar gun.  He joked, "Had I known what you were going to do with it (radar) I would never have invented it!"

He died in Inverness in 1973 aged 81 and is buried beside his third wife.