Site Records


SiteName: Criggion Radio Station

Criggion
Montgomeryshire, Wales
SJ283144

Sub Brit site visit 6th May 2003

[Source: Andrew Emmerson]

THE FUTURE Alert Communications (a consortium led by Merlin Communications) became the VLF provider from April 2003, when DCSA Radio's contract with BT for VLF services from Criggion and Rugby terminated. From 31 December 2003 Alert will provide an end-to-end VLF received signal service to Royal Navy submarines under an innovative PFI contract, negotiated and managed by the STRS IPT of the Ministry of Defence. Alert Communications will provide the service through one new transmitter site (Skelton) and one updated one (Anthorn), also provide the receivers on all submarines under the contract.

Photo:Two of the VLF aerial towers with the VLF building to the right
Photo by Nick Catford

PRACTICAL DETAILS The VLF aerial is slung between three 600ft self-supporting steel towers and anchorages built on the top of an adjacent steep hill (by comparison the VLF aerial at Rugby employed twelve 820 ft. lattice steel masts).


VLF Transmitter Hall - picture from Practical Wireless

It is understood that Criggion's HF transmitters were taken to Ongar and Rugby radio stations after they were no longer required at Criggion.

The freestanding towers are equipped with staircases; the guyed masts have lifts, described as 'a cage with a lawnmower motor'.

The trio of Criggion together with sister stations at Rugby and Anthorn gave worldwide coverage on VLF. Each had slightly different radiation patterns and it is said that Criggion provided best coverage in the South Atlantic.

The Criggion site, though ideal for its purpose at the time it was acquired has brought one or two problems-not the least of which is that it is subject to severe flooding at certain seasons of the year, so much so that an amphibious vehicle-a DUKW-was necessary at times to convey staff to and from duty. Once, before the DUKW was provided, the station was cut off and had to be relieved by rubber dinghies dropped by the RAF.

Every now and then the DUKW itself got bogged down and on one occasion a staff member had to swim to the nearest stout tree with a tow rope. The road past the radio station was constructed by the Ministry of Public Building and Works for the exclusive use of the radio station, the public road running at the foot of the cliff. The condition of the latter deteriorated from the heavy traffic by quarry lorries and seven years ago it was closed, with all public traffic diverted along the radio station's access road.

Standby generators - Picture from Practical Wireless


  • Further technical details in Hari Williams' article 'Craggy Criggion'-see 'Further Reading' below.

STATION CLOSURE This is how the Shropshire Star reported the station's closure on 26th February 'Top secret radio site to close - A top secret communications station that has been a landmark on the Powys/Shropshire border for more than 50 years is to close. The high security Criggion radio station, near Welshpool, will stop operating at the end of March.

Although the exact role of Criggion 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.

Around 15 employees who work on the site will either be redeployed or will leave on 'voluntary terms'. There will be no compulsory redundancies, BT said today.

Photo:The VLF aerial tuning coil and Variometer
Photo by Nick Catford

Opened by the old GPO in 1945 [wrong], it was run by the Post Office and then BT when it split from the Post Office in 1984.

Though a BT official confirmed today that the site was to close, he would only say: "Criggion will close at the end of next month when the contract with our client comes to an end."

He would not confirm that the client was the Ministry of Defence, something that neither BT nor the MOD have ever publicly admitted. "From the end of March transmissions from the site will cease and in the months that follow the masts will be dismantled," added the spokesman.

During the 1960s, when its work was at its height, 160 people were employed on the site. Visitors were not permitted and it is surrounded by high fences and monitored by surveillance equipment. It became a target for anti-nuclear protesters, including Kath McNulty from Dolgellau who was one of the Trident Ploughshare 2000 protesters. She said today the protesters' aim had been to get rid of Trident nuclear submarines. "We felt that we wanted to do something locally in Wales and Criggion. We were talking to the people there to try and convince them that they did not want to be involved in this because they were working for BT and were not part of the war machine. I am very sad if the station is closing. I am very sad if people are losing their jobs and sad that we have not achieved our goal of persuading the government that we do not need the deterrent. The low frequency system will just be moved somewhere else. Our aim was not to close down the station.'

[Reproduced here with acknowledgement.]

Further information and pictures about this site continues here

[Source: Andrew Emmerson]

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