Rugby Radio Station was a large radio transmission facility just east of the Hillmorton area of the town of Rugby, Warwickshire in England. The site straddled the A5 trunk road, with most of it in Warwickshire, and part on the other side of the A5 in Northamptonshire. First opened in 1926, at its height in the 1950s it was the largest radio transmitting station in the world, with a total of 57 radio transmitters, covering an area of . Traffic slowly dwindled from the 1980s onwards, and the site was closed between 2003 and 2007. The tallest masts on the site were tall, and could be seen from up to away, making the site for many years a major local landmark. Since closure, part of the site has been used for a large housing development called Houlton, named after Houlton, Maine, USA the American town which received the first transatlantic phone call from the station in 1927. History Following the end of the First World War the British government set about implementing plans for an Imperial Wireless Chain to link the countries of the British Empire. It was decided that the new wireless service would be state-run by the Post Office. The site east of Hillmorton, was chosen in 1923. Part of the site had previously been occupied by RAF Lilbourne between 1915 and 1920. Its large very low frequency (VLF) transmitter came into service on 1 January 1926 and was originally used to transmit telegraph messages to the Commonwealth as part of the Imperial Wireless Chain. After the 1950s this transmitter, active as callsign GBR on 16.0 kHz, using Morse code and later on 15.975 kHz with frequency-shift keying FSK and minimum-shift keying MSK, was used for transmitting messages to submerged submarines. Criggion radio station acted as a reserve. The GBR transmitter was shut down on 1 April 2003 and was replaced by a new one at the Skelton transmitting station. In 1927, a second transmitter was installed to initiate the first transatlantic commercial telephone service; linking New York and London on 60 kHz using single-sideband modulation. This transmitter was decommissioned in 1956 and became the time signal transmitter MSF. This new function developed from the decision, in 1951, to use the station to transmit modulated standard frequencies for scientific reference purposes. In 1972 these transmissions were consolidated onto the present frequency of 60 kHz and a further reference,