Invention Of Radar

Radar now has an important role in keeping the seas and the skies safe for traffic, but it began life with the opposite intention when its inventor, Robert Watson-Watt, was as to investigate the possibility of building a 'death ray'.


Robert Watson-Watt (Scotland) is generally credited as the inventor of radar, but as with so many inventions, there were precursors and false starts before Watson-Watt invented the first practical system. As early as 1904, Christian H. Ismeyer (Germany) petented a system of 'employing a continuous radio wave to detect objects' as a collision-warning system for ships. A patent filed in 1926 by John Logie Baird (Scotland) describes 'a method of viewing an object, by projecting upon it electromagnetic waves of short wavelength', which constitutes a form of radio detection, and in 1933 Rudolf Kuhnold (Germany) developed radio detection equipment and demonstrated it in Kiel Harbour the following year.

However, a crucial function of radar is rangefinding, and the first equipment to enable detection and ranging was invented in 1935 by Watson-Watt, who had previously researched the use of cathode ray direction finder to detect thunderstorm (patented in 1926). In January 1935 Watson-Watt was asked by the committee for the Scientific Survey of Air Defense to investigate whether radio waves could be used to destroy enemy aircraft. On 12 February he replied that radio waves would be insufficient to actually destroy an aircraft but the planes could be detected by bouncing radio waves of them, measuring the delay before the echo returned, and thereby calculating the direction and distance of the aircraft. Two weeks later, on 26 February the demonstrated radar by plotting the course of a Heyford bomber from eight miles away, and on 17 September he filed a patent for the first practicable radar system.

Until 1943 radar was known in Britain as RDF, or radio direction finding. Meanwhile, it was developed independently in Germany and in the USA, where US Navy Commander S.M. Tucker coined the phrase radar from radio detection and ranging.

Source - The Book Of Inventions by Ian Harrison