SATELLITE COMMUNICATIONS

The operation and maintenance of the 40ft terminal and its ancillaries was carried out by RCA Ltd under contract to the Mininstry Of Aviation Supply and the Test Laboratory was manned by SRDE scientific and technical staff. Measurements were made with this Facility on the SKYNET spacecraft and other nation's spacecraft.

Precise and accurate measurements of the performance in orbit of SKYNET were carried out to check whether the spacecraft met contractual requirements. Another major function of the programme was the maintenance of a long-term data base from which any degradation of performance of the satellites could be promptly seen and remedied.

An extensive programme on the design of antennas for fixed and mobile earth stations, and a highly portable "man-pack" was also undertaken. The experience gained from measurements with existing satellites enabled improvements to be made on the next generation of spacecraft.

Satellite telephone links

The Skynet satellite using a speech system developed by SRDE was used to set up telephone links for three-way conversations between the Ministry of Defence in London, the Services' base in Singapore and the rescue fleet flagship. The use of Skynet in this way allowed many quick decisions to be made on the supply of food, stores and medicines to the stricken area. SRDE was also responsible for the provision of long distance digital speech, data, telegraph and facsimile circuits for the Ministry of Defence. Information was entered into the system through equipments in the Terminals, it was then coded and transmitted to Communication Centres where it was routed overseas by either satellite or HF radio paths.

The Radomes (the white domed beehives that tracked satellite signals) were overlooking the beach at Friars Cliff, Dorset.

Additional studies

In addition to this programme on Satellite Communications the following topics were studied:

• Spherical antenna and multimode tracking.
• Multiple access techniques for military satellite communication.
• Techniques for long distance digital communication.
• Satellite test facility.
• Low noise MASER amplifier.
• Reflector metrology.

EQUIPMENT AND DEPLOYMENT

The hardware shown below was produced as a result of the R.and D. programme on Satellite Communications and included portable satellite terminals and static installations.

In addition to the Gulf war this equipment was used in various areas of conflict - Bosnia (below left) and San Carlos Falklands (below right).