Vitatron UR400 Linear Pen Recorder

Vitatron UR400 Linear Pen Recorder

This piece of equipment was used by Derek Slater and Geoff Perry for the Kettering Satellite Tracking Group as part of their tracking of 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.

The Vitatron Linear Recorder was used in conjunction with an ex-minicab communications receiver and a tape recorder to routinely and automatically monitor voice traffic from Soyuz vehicles travelling to the Salyut space stations between the mid-1970s and mid-1980s. The setup operated overnight and at weekends, meaning that the Group missed very few opportunities to listen in and learn from what they heard. Soviet crews working on Salyut aligned with Moscow Time, meaning that they could normally be monitored during daytime in the UK. However, some launch windows dictated that the visiting Soyuz passed over Russia and Kettering during the night. To compensate for this a communications receiver was left running so that when a signal was received it opened the 'squelch' which, in turn, started the tape recorder. The Vitatron Linear Pen Recorder ran continuously and the trace it made showed when there was a signal present. The tape recorded conversations were available for translation and the pen trace allowed the times to be logged.