John Ashworth RatcliffeCB[2]CBEFRS[3] (known to intimates as "Jar";[4] 12 December 1902 – 25 October 1987) was an influential British radiophysicist. (Several sources misspell his name as Radcliffe.)
Ratcliffe was born in Bacup, the elder son of Harry Heys Ratcliffe, a partner in the stone quarrying firm of Henry Heys and Co., and Beatrice Alice. daughter of Richard Ashworth, founder of the firm of Mitchells, Ashworth, Stansfield and Co.[5]
That year Ratcliffe started research on radio wave propagation under Edward Appleton. They and M A F Barnett developed methods to understand why ‘fading’ of radio signals from a fixed transmitter occurred during hour of darkness. In 1927 Ratcliffe was made head of a group in the Cavendish Laboratory known as the radio ionosphere research group. They studied how radio waves were reflected from the ionized layer in the upper atmosphere (previously called the Heaviside layer), and how the layer was formed.[6] The work of the group and their publications are described at some length in the Royal Society’s biographical memoir.[3]
At the outbreak of war in 1939, dozens of radar stations formed a network, known as Chain Home (CH), covering the eastern and southern coasts of Britain. Physicists from the Cavendish and elsewhere were assigned to spend a month at one of the stations: Ratcliffe was sent to the one near Dover, but was soon made part of the Telecommunications Research Establishment (TRE) in Dundee where he was in charge of a new form of CH known as Chain Home Low (CHL), used to detect aircraft flying at altitudes below those detectable by CH stations. His work took him to various locations during the war: Swanage, Petersham, back to Dundee, and Malvern.
At the end of the conflict, Ratcliffe was back at the Cavendish, which had been enlarged, enabling him to restart research with a larger group. Martin Ryle and some others from TRE joined them and decided to follow up the discovery of radio emission from the sun. Ryle was in charge of a section concerned with radio astronomy.
In October 1960 Ratcliffe left Cambridge to take up the post of director of the Radio Research StationatDitton Park. He resigned in 1966.
John Ratcliffe married Nora Disley at St Nicholas Church, Newchurch on 28 August 1930. They had two daughters, Margaret and Elizabeth. Elizabeth died in 1966, and Nora in 1977.
Ratcliffe died at his home, 193 Huntingdon Road, Cambridge, on 25 October 1987.
