The Goonhilly 85-ft. steerable dish aerial

The choice of the basic type of aerial for a satellite communication ground station is of major importance in view of its influence on the overall performance, cost and time to complete the installation. In the case of the Post Office satellite communication earth station at Goonhilly Downs, Cornwall, a decision was made early in 1961 to use an 85-ft diameter steerable paraboloidal dish aerial, without a radome for tests with the Telstar and Relay, and other communication satellites.

Tests with smaller paraboloidal dish aerials with the feed in the aperture plane had shown that a satisfactory electrical performance could be obtained, and experience with the 250-ft diameter radio telescope at Jodrell Bank had shown that the mechanical problems could be overcome.

An important factor in the present case was the limited time--less than one year--available for the design, manufacture, construction and testing of the aerial.