Radar Recollections - A Bournemouth University / CHiDE / HLF project


A.P.Rowe and his Sunday Soviets - Rebecca / Eureka

Testing Eureka Equipment
Testing Eureka Equipment

Dr John Pringle was a Cambridge biologist who worked at TRE Worth (Leeson House unit) with Hanbury Brown and E.K. Williams. Early in 1940, they were working on a project that involved an airborne transmitter/receiver set and a ground beacon that could recognize each other's signals 'automatically'. This is not strictly 'radar' because it does not rely upon reflected signals but upon a separate 'response' signal. The primary idea was for a friendly aircraft to be able to drop supplies to a beleaguered force on the ground with pinpoint accuracy.

The airborne unit (Rebecca) sent out an 'interrogation pulse' and when this was received by the ground unit it caused a pulsed and identity-coded reply (to be generated by a transponder) which 'sends' on a different frequency. This new signal was received by two aerials on the aircraft and displayed on a Cathode Ray Tube (CRT) in a form which showed range and direction. Later designs allowed 5 different transmit / receive frequencies to be selected. Some of the ground sets were disguised as biscuit tins because they were bulky. Nevertheless, the French partisans and other covert operators such as the Special Operations Executive (SOE) found the system invaluable when working in enemy occupied territory because ground lights were no longer
necessary. The ground sets were usually fitted with detonation devices to prevent capture….

The system was regularly used throughout the war and particularly during Operation Overlord… (the D-Day landings) Murphy Radio Ltd built the beacon equipment and Bush Radio Ltd supplied the aircraft display screens. The prototypes were ready by June '42 and had a range of about 80 miles.

Eureka Equipment
Eureka Equipment
A Self destructed Eureka Equipment
Eureka equipment was designed to self destruct to prevent it form falling into enemy hands