Site Records

SiteName: Rugby Radio Station

Rugby
Warwickshire
OS Grid Ref: ('C' Building) SP553747

LATEST NEWS: Eight of the twelve 820' masts at Rugby were demolished by DSM demolition contractors during the evening of of 19th June 2004. See here for full details, pictures and video 30/6/04.

Sub Brit site visit 28th May 2003

WHAT The tall masts of Rugby Radio Station (some 820ft high) are a familiar landmark to travellers on the M1 motorway, A5 trunk road and West Coast Main Line railway. In the near future all but two will be demolished, making this an apt time to investigate Rugby. The radio station described below belonged originally to the Post Office and after privatisation, to British Telecom.

WHERE Rugby radio station lies astride the A5 trunk road (the ancient Watling Street Roman road). The road marks the western border of the ancient Danelaw territory and is the county boundary, meaning that half the station is in Warwickshire and the other in Northants.. The nearest habitation is the village of Hillmorton, now a suburb of Rugby.

ITS FUNCTION Rugby's sole continuing function is to transmit time signals of guaranteed accuracy, derived from the standard time clock run by the National Physical Laboratory (NPL). As well as setting vast numbers of radio-controlled clocks in Britain the NPL's time signal has many other interesting applications. When you call the speaking clock, or hear the time 'pips' on the radio, for instance, the time is derived from the NPL's atomic clock. Rugby's radio telephony roles were given up some years back.

Some secrecy has always surrounded Rugby's third role, although even then a number of publications suggested that its role was chiefly defence-related, providing worldwide radio coverage on the very low frequency (VLF = long wave) band to ships and submarines (the station had nothing to do with the BBC and was never used for broadcasting to the public). A newspaper article this year (2003) sums up what might be considered common knowledge when it states:

Commercial postcard showing the VLF transmitter building shortly after opening

"Although the exact role is wreathed in secrecy, it is believed it acts as a contact point for nuclear submarines across the world and was a 'Category A' target during the Cold War."

The Trident Ploughshares website is more explicit and asserts the station commanded Trident submarines, saying: "The main sites for command and control of Trident submarines include Criggion, Rugby, Anthorn and Inskip. These sites normally consist of radio masts and little else. Command and control systems begin with the Ministry of Defence in Whitehall, London. Actual operational instructions are transmitted from RAF Northwood. However, Trident is also linked into the US command and control system and with various NATO systems."

However, Peter Hennessey's book The Secret State (revised edition, 2003) blows away any remaining doubt with the statement, "Among [the Russians'] military targets were the very low frequency signals installations at Rugby and Criggion, whose purpose was and is to relay the Prime Minister's instructions to the commanders of the deterrent-bearing submarines."

The VLF (Long Wave) aerial systems are supported by twelve 820 ft. masts spaced at quarter mile intervals so that eight of them form an irregular octagon, while the remaining four provide two extensions to the north.

Each mast is supported by steel-wire stay-ropes at five levels and is designed to withstand a uniform wind load of 60 lbs/sq. ft. and a horizontal pull at the top of 17 tons. Each mast, complete with stays, weighs 200 tons. A sway of several feet at the top is possible. The aerials are lowered or raised on electrically driven winches mounted on platforms built on to each mast at a height of 33 feet. These winches are also used to operate lift cages, each capable of carrying three persons. An earth-wire system is used, made up of a series of radial 100 lb hard drawn silicon bronze wires, spaced 50 feet apart and buried six inches in the ground. The buried wires form a ring around the transmitter building and a wide 'path' under each of the masts.

RUGBY'S HISTORY In the early part of the 20th century, the British government showed considerable interest in developing a series of powerful radio transmitters that would join the British Empire together via radio links.

Some of this work was completed by the Marconi company but the government decided to build its own Post Office-run communication station to avoid being reliant on Marconi.

Hillmorton, near Rugby, along with Leafield in Oxfordshire, were chosen as excellent sites for transmitting.

Both were located in central England with large areas of flat land (Rugby was a former Royal Naval air station of First World war vintage). The Post Office long-wave wireless station at Hillmorton, near Rugby with worldwide range, was brought into service on 1st January 1926. At the time the station was the most powerful in the world, being equipped with a huge water-cooled transmitter (call sign GBR), dissipating 10kW and using 54 thermionic valves on a wavelength of 18,750 metres.

The VLF aerial feed into the transmitter building

The coil room in 1929

Initially, it commenced transmission in Morse code on 16kHz with an aerial power of 350kW. At the time it was the world's most powerful transmitter using thermionic valves. Later in the same year two-way conversation by radio telephone was also established for the first time between England and the USA from Rugby. There were twelve 820 feet masts each weighing 200 tons, with a three-man lift in the centre, supporting 27 miles of copper cable.

During World War II many of Rugby's transmitters were used by the armed forces. In January 1940 the main antenna collapsed under the weight of ice and in March 1943 a disastrous fire put the VLF transmitter out of action for a while; its role was taken over by Criggion

Additional transmitters were installed in a new building in 1953 and the power supply was renewed.

Further information and pictures about this site continues here

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