Speaker: Mike Diprose

H2S was an airborne, pulsed radar navigation system, which gave a map of the terrain below the aircraft. The raiding force, therefore, became independent of 'Gee' to a large extent as they could continue navigating past 'Gee' maximum range or if it was jammed.

Originally, it had been hoped it could be used for accurate, blind bombing, but the resolution of the early sets was not good enough for this purpose. It was possible to tell, however, when the aircraft was over a town or city and so it was still extremely useful for navigating to targets beyond 'Gee' range and opened up the whole of enemy occupied Europe to Bomber Command.

The lecture will describe the H2S system and the story of its development and introduction into squadron service and the effect it had on the bombing campaign. Since the heart of the radar was the secret, high power magnetron valve, this too will be described in the lecture. It was invented by the British and manufactured by the Americans.