The History of Air Intercept (AI) Radar and the British Nightfighter

This is the history of Air Intercept (AI) radar and its use in night-fighter aircraft in defense of the UK. Beginning in 1935, it describes the events leading up to the creation of the Air Ministry Research Establishment and the work of the Establishment’s Airborne Group and the building of the first 1.5 meter AI Mk 1 and later versions that saw use during the winter Blitz in Blenheim night-fighters and Mosquito during the Baedeker Raids. It covers the introduction of cent metric technology at the Telecommunications Research Establishment and the creation of cent metric AI (Mks VII – IX) and their installation in the Beaufighter and later marks of the Mosquito. It describes the creation of the Radiation Laboratory at the Massachusetts Institute of Technology, and the development the SCR 720 radar and its adoption by the RAF.