Chamberlain took up the matter with his friend Lord Nuffield, who provided £60,000 () for the project, enough for the cyclotron, a new building to house it, and a trip to Berkeley, California, so Oliphant could confer with Ernest Lawrence, the inventor of the cyclotron. Lawrence supported the project, sending Oliphant the plans of the cyclotron that he was constructing at Berkeley, and inviting Oliphant to visit him at the Radiation Laboratory. Oliphant sailed for New York on 10 December 1938, and met Lawrence in Berkeley. The two men got along very well, dining at "Trader Vic's" in Oakland. Oliphant was aware of the problems in building cyclotrons encountered by Chadwick at the University of Liverpool and Cockcroft at the Cavendish Laboratory, and intended to avoid these and get his cyclotron built on time and on budget by following Lawrence's specifications as closely as possible. He hoped that it would be running by Christmas 1939, but the outbreak of the Second World War quashed his hopes. The Nuffield Cyclotron would not be completed until after the war. In 1938, Oliphant became involved with the development of radar, then still a secret. While visiting prototype radar stations, he realised that shorter-wavelength radio waves were needed urgently, especially if there was to be any chance of building a radar set small enough to fit into an aircraft. In August 1939, he took a small group to Ventnor, on the Isle of Wight, to examine the Chain Home system first hand. He obtained a grant from the Admiralty to develop radar systems with wavelengths less than ; the best available at the time was . Oliphant's group at Birmingham worked on developing two promising devices, the klystron and the magnetron. Working with James Sayers, Oliphant managed to produce an improved version of the klystron capable of generating 400W. Meanwhile, two more members of his Birmingham team, John Randall and Harry Boot, worked on a radical new design, a cavity magnetron. By February 1940, they had an output of 400W with a wavelength of , just the kind of short wavelengths needed for good airborne radars. The magnetron's power was soon increased a hundred-fold, and Birmingham concentrated on magnetron development. The first operational magnetrons were delivered in August 1941. This invention was one of the key scientific breakthroughs during the war and played a major part in defeating the German U-boats, intercepting enemy bombers, and in directing Allied bombers.