O’Brien's friend, Harvey F. Schwarz, was chief engineer of the Decca Record company in England. In 1939 O’Brien sent him details of the system so it could be put forward to the British military. Initially Robert Watson-Watt reviewed the system but he did not follow it up, deeming it too easily jammed (and likely due to the existing work on the Gee system, being carried out by Watt's group). However, in October 1941 the British Admiralty Signal Establishment (ASE) became interested in the system, which was then classified as "Admiralty Outfit QM". O’Brien brought the Californian equipment to the UK and conducted the first marine trials between Anglesey and the Isle of Man, at frequencies of 305/610 kHz, on 16 September 1942.