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Original Text (Annotation: EAW052580 / 1383627)
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Cooling Radio Station: ‘…the most advanced and technically complex radio ever built.’ (English Heritage Research Department Report Series No 110-2010) This vital communications link, between the US and British governments at the very highest level, operated from 1942 until the early 1960s. Although a transatlantic telegraph cable had been in use since 1866, there was no telephone cable until 90 years later, in 1956. An initial shortwave system was set up in 1929, but was of poor quality. The Post Office set up and ran Cooling Radio Station solely for the reception side of two way, shortwave, voice channels with the United States.
Land was purchased in 1938 and the building was completed in 1939. The receiver used 1,079 valves and was considered to be the most complex radio built. It was connected to the adjacent MUSA (Multiple Unit Steerable Antenna) and could receive 4 incoming radio telephone channels.
It was officially in use on the 1st July 1942. This may well have been because German intelligence services were able to break the scrambler / encryption device available in 1939. By 1943, Bell Laboratories in the US had developed SIGSALY, a far more secure scrambler system. (This system was so well screened and secure that German records captured at the end of WW2 showed that they were not aware that transmissions were person to person, direct voice contact.) SIGSALY was installed in the basement of Selfridges department store in Oxford Street with extensions to 10 Downing Street, the Cabinet War Rooms and the US Embassy amongst others.
The US transmitter was located at Lawrenceville, New Jersey, while UK transmissions were made from Rugby to the US receiver at Manahawkin, New Jersey.
For sources, see:
English Heritage Research Department Report Series No 110-2010, ISSN 1749-8775, COOLING RADIO STATION, HOO PENINSULA, KENT - An Archaeological Investigation of a Short-Wave Receiving Station by Derwin Gregory and Sarah Newsome.
A Multiple Unit Steerable Antenna for Short-Wave Reception by H. T. Friis and C.B. Feldman, Bell System Technical Journal 16, 3rd July 1937. https://archive.org/stream/bstj16-3-337#page/n0/mode/2up
A Single Sideband Musa Receiving System for Commercial Operation on Transatlantic Radio Telephone Circuits by F. A. Polkinghorn, Bell System Technical Journal 19, 2nd April 1940. https://archive.org/stream/bstj19-2-306#page/n0/mode/2up
https://en.wikipedia.org/wiki/SIGSALY
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