Rugby transmitting station

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A view of the tallest masts (alternative view)

The Rugby transmitting station is a large very low frequency (VLF) transmission facility near the town of Rugby, Warwickshire in England. It came into service on January 1, 1926 and was originally used to transmit telegraph messages to the Commonwealth. After the 1950s this transmitter, active as callsign GBR (short for Great Britain) on 16 kHz, was used for transmitting messages to submerged submarines. Around 1930, a second transmitter was installed for transatlantic telephony on 60 kHz using carrierless 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, that of a time signal, was added. In 1977 this took the form of the rolling slow code in use today.

The GBR transmitter was shutdown on April 1, 2003 after the Royal Navy decided not to renew their contract with BT in favour of a new contract with VT Communications. On 1 April 2007 BT's contract to transmit the time signal also passed to VT Communications, using their Anthorn transmitter in Cumbria.

The aerial system at the VLF transmitter existed between 1926 and 2004 and consisted of twelve 250-metre high, guyed steel-framework masts insulated against ground and carrying an aerial wire. This wire was mainly destroyed by heavy iceloads in the winter of 1940. From the shutdown of GBR, the facility was only used for transmitting the MSF time signal. Therefore, 8 of the 12 masts were obsolete and demolished on the night of June 19, 2004 to June 20, 2004.

A trial of transmission of the LORAN-C navigation system is being run at the station. It started in June 2005 and is due to run until March 2007. ^[1]