Sir Robert Alexander Watson-Watt (1892-1973) was a British scientific civil servant who pioneered the development of radar.

Robert Watson-Watt, the youngest son of a carpenter, was born on April 18, 1892, at Brechin, Angus, Scotland. He studied electrical engineering and physics at University College, Dundee, and became assistant to the professor of natural philosophy there in 1912. In 1915 he was assigned to the Meteorological Office to assist in the location of thunderstorms by their radio emissions for the information of aviators. This led to fundamental research into atmospherics (the transient radio emissions from lightning discharges) at the Radio Research Station, Slough, England, under the aegis of government departments. By the 1930s much had been achieved there through inter alia, the development of the cathode-ray oscillograph and aerial systems. Atmospherics were located by direction finding at two or more receivers and associated with the movements of cold-air fronts.

In 1935 Watson-Watt was asked to consider the possibility of radio destruction of aircraft (the "death ray"), but with A. F. Wilkins he soon confirmed its impracticability. However, further calculations indicated the possibility of radio detection, and in February 1935 Watson-Watt's memorandum on the "location of aircraft by radio methods" was taken up by the Tizzard Committee for the scientific survey of air defense. Watson-Watt showed that a metal aircraft approximated to a linear oscillator and indicated that the secondary radiation induced when aircraft were illuminated from the ground with 50-meter radiation could be detected at ranges of tens of miles. He proposed transmitting short pulses both to increase peak output and to use the time delay in the return of the echo from the aircraft to determine range. Cross bearings from other stations could fix positions. Pulse techniques had been developed for echo-sounding the generally reflective ionosphere, but extensive refinement was required for its application to the detection of small targets. At an establishment on the North Sea coast Watson-Watt, with Wilkins, L. H. Bainbridge-Bell and E. G. Bowen, brought the system to reality and added direction finding from crossed horizontal halfwave aerials. By 1936 a home defense chain of radar stations had been approved; largely completed by 1938, it played a vital role in the Battle of Britain.

The development of radar was very much a team effort with Watson-Watt as captain. Throughout the war he was increasingly concerned in coordinating the expanding effort in the radar field. He visited the United States in 1941-1942 as an adviser. In 1946 he left government service to practice as a consultant. He was elected a fellow of the Royal Society in 1941 and was knighted in 1942.

Watson-Watt claimed the invention of radar, but, as with other classic science-based inventions, it evolved. There were precursors and simultaneity of discovery in several countries. Suffice it to say that no other saw the possibilities so clearly, and no government took up the implications more quickly. Perhaps more than any other in the history of invention, Watson-Watt was the right man in the right place at the right time.

For his work, Watson-Watt received the United States Medal for Merit in 1946. He lived in Tuxedo, New York, and briefly in Canada. But he died December 5, 1973, in his homeland of Scotland after a long illness.

Further Reading

• Watson-Watt describes the development of radar from a personal point of view in his Three Steps to Victory (1957) and The Pulse of Radar: The Autobiography of Sir Robert Watson-Watt (1959). A biography is John Rowland, The Radar Man: The Story of Sir Robert Watson-Watt (1963). Briefer accounts appear in Egon Larsen, Men Who Changed the World: Stories of Invention and Discovery (1952), and Patrick Pringle, Great Discoveries in Modern Science (1955).