History

The microwave bands used for satellite communication were shared with those used for inland point-to-point links (this was one of the factors influencing the location of the Earth Station). To avoid a local conflict the link at Goonhilly operated in the "Upper" 6 GHz band. Contract 23518 was awarded to Pye in 1962 at an original price of £18,131. The final payment was made in February 1964 with the total paid having risen to £18,464. Other information suggests te equipment used was the Pye PTC M1000A, a 1950s Raytheon design, manufactured under licence. Other suppliers such as GEC and STC did not offer U6 GHZ equipment at this stage. The Pye equipment was given the Post Office designation RS 10/14 and able to provide a link for 625-line television or 600 telephony circuits. The PTC M1000A appears to have been a transportable design (with options for permanent use) and it is possible the initial link was established using the portable version with temporary structures.

At Goonhilly a relatively short tower of conventional "pylon" design was built close to the original control room (itself based on the standard microwave Radio Station building). Two intermediate sites were reqired at Mount Stamper and Burydown. These were provided with a version of the "Standard Tower" - both structures are relatively short but of large cross-section. This type of tower was designed to support horn antennas but it seems very unlikely any were fitted. Both sites have the standard building.

It is likely the traffic from Goonhilly was carried over existing circuits between Plymouth and London since there do not appear to be any details of contracts to expand the capcity over this section until 1964. Telstar 1 was essentially an experiment and its "low earth orbit" meant that use was restricted to relatively short periods - 30 minutes in each 2.5 hour orbit.

The plans for Intelsat I ("Early Bird") led to expansion of the entire route between London and Goonhilly with a number of contracts placed in 1964. Contract 23573 was awarded to Pye, for a "temporary" U6 GHz link in July but STC was awarded contract 23587 in December. Little detail is known for the Pye contract, other than the original price of £69,848 and final payment of £69,567 in February 196.

Contract 23587 appears to relate to a more permanent arrangement and was subject to competitive tender. Marconi was unable to offer a U6 GHz system. GEC bid £88,070 but was unable to meet the completion date of 1 April 1966. The bid from STC was £95,929 (final price paid as of September 1966 was £100,548). GEC and STC were also bidding for the section between Bristol and Plymouth and the following comment was made in respect of both contracts:

"The GEC [offer] for an Upper 6,000 Mc/s system could not be considered due to the date it would become available i.e. Jan 1967"

Diagram E5017 "Satellite Basic Phase Line Diagram" dated July 1965 shows the system in use betweeen Goonhilly and Plymouth as RS 10/20 which was the STC RL6D - a 10 W U6 GHz system also used between Bristol and Plymouth. This suggests the work may have been completed ahead of schedule: Intelsat 1 itself was operational at the end of June 1965.

A summary of estimated expenditure for 1966 to 1970 shows further expansion of the section between Bristol and Plymouth "for Satellite Scheme" but there is no specific mention of Goonhilly to Plymouth in this period. It is likely additional channels continued to be added to the STC system during the 1970s with migration to digital links in the 1980s, however within the wider network it appears there was a plan to link from Goonhilly across to St Just and via a second route running along the north coast of Cornwall. Due to the design of the tower at Goonhilly and the need to use a separate band for the terrestrial link it is unlikely the first "hop" ever used more than two dishes. Photos of Mount Stamper in 2005 show dishes facing Burydown only: it is likely the alternative route (or fibre) was used for the final years of operation. In 2006 BT announced its intention to cease using Goonhilly by 2008. The site is now owned by Goonhilly Earth Station Ltd.