ASV Mks. I and II, the First Airborne Maritime Surveillance Radars

ASV Mk. I was the first airborne maritime surveillance radar, entering service with the RAF in the UK in early 1940. The design of the radar is described and its predicted performance is compared with reported operational performance from its time in service. Later in 1940 a better-engineered and higher performance variant, ASV Mk. II, entered service. This radar is also described and its performance assessed.