Marconi CR100/2 Communications Receiver

Marconi CR100/2 Communications Receiver

This ex-government surplus army communications receiver was part of the equipment Geoff Perry and Derek Slater used at the Kettering Grammar School Group to track Soviet space activity.

Slater and Perry worked at the Kettering Grammar School together and shared an interest in space. They used borrowed and inexpensive equipment to teach their students how to track satellites. In the process of doing this, the Kettering Satellite Tracking Group was born - which in turn led to the discovery and announcement of a secret Soviet launch site at Plesetsk, securing the Group worldwide media attention.

This type of receiver was built in large quantities during World War 2 and many found their way into the second-hand radio enthusiast market after the war. This particular version was built originally for the British Army and its purchase by Derek Slater is fundamental to the Kettering Group coming together. If he hadn't possessed it in 1960 when Geoff Perry proposed tracking Korabl-Sputnik 1 (sometimes known as Sputnik 4 in the West), then things might have taken a different course. In 1957 Slater had been disappointed not to be able to listen to signals from Sputnik. He ran a radio club at his school and was frustrated not to be able to share the experience with his pupils because his receiver did not tune as high as Sputnik's 20 MHz frequency. He bought the CR-100 in 1958 as a result and it was therefore available when the next series of Soviet satellites using 20 MHz appeared in 1960 and Perry sought him out to help track them.

It remained in use as the main piece of receiving equipment until Autumn 1967 when it was replaced by a Racal RA-217. In the late 1960s it was pulled out of retirement temporarily when the Group tracked some of the early Soyuz missions involving multiple spacecraft and simultaneous transmissions at different frequencies. For tuning, it was not stable enough to use in its own right so it was used in conjunction with the highly stable US Army BC-221-T Frequency Meter.