Tuesday, February 22, 2011

The Story of Criggion

A nostalgic piece from AWR's Wavescan program

A Longwave Failure: The Story of (Partly) Unsuccessful Criggion in Wales

The small village of Criggion is located in north eastern Wales, quite close to the border with England. Criggion has been noted for two areas of interest; a railway system the rolling stock of which is described as one of the most bizarre in English railway history, and an international radio station that was always shrouded in secrecy.
The railway line, known locally as the Potts Line, ran across a country area between Nantmawr & Shrewsbury Abbey, and it was inaugurated in the 1860s. The line was never commercially profitable, its service was unreliable, its bridges unsafe, and its carriages described as most bizarre. A branch line ran from the main Potts Line to Criggion and this was inaugurated in 1866. The entire system was shut down in 1934 at the end of some 60 years of spasmodic mediocre service.
The radio station was constructed hurriedly during the hectic events in the middle of last century, it acted rather unsuccessfully as a backup for a much larger and better known station, it carried occasional program relays to the United States, and it was finally closed in 2003 after 60 years of on air service. This what happened.
During the earlier part of the European conflict, apprehension was felt in England regarding the large major radio station operated by the British Post Office at Rugby, in central England. The mighty Rugby station was vital for international communication and at times, for program relays, but it was at the same time, also vulnerable to damage and destruction from attack by enemy planes.
Consequently, the British authorities entered into plans for the erection of a backup station that could be used if Rugby were disabled. This new additional radio station was installed in a secret isolated area, and its activities were always shrouded in mystery. Even the operating staff were not aware of the content of the signals that were transmitted over their station.
The location for the new radio station was near the small village of Criggion in a very picturesque area adjacent to the abrupt Breidden Hill, and only a few miles from the Severn River. Work commenced on this new station under a crash program in 1940.
Initially, there would be two shortwave transmitters, one longwave transmitter, and one very longwave transmitter. Very robust buildings, dispersed over the 400 acre property, were solidly built and three Eiffel style towers planned for erection at a navy station in Trincomalee in Sri Lanka were diverted for installation at Criggion. These three towers stood at 600 ft tall. In addition, instead of a 4th tower, a strong anchor point was installed on the top of the 900 ft hill for use as part of the longwave antenna system.
A widespread metal mesh earthing system was placed at 9 inches underground as a counterpoise to the high wire antenna system. Much of the property was let out for animal grazing, but no heavy machinery was permitted in order to avoid damage to the earthing mat.
In July 1942, the two shortwave transmitters were activated. These two units were an STC CS3B and a Marconi SW8. During the early part of the following year, the longwave transmitter was activated with test transmissions under the callsign GBZ.
However, at this stage in March 1943, there was a fire in the Rugby station that disabled the high powered longwave transmitter GBR. The fire, caused by high levels of RF radio frequency energy, broke out in the wooden rafters above the huge longwave transmitter, though by quick action, the fire was contained within the one building.
However, the longwave transmitter GBR was damaged and unusable without extensive repair. Hence it was that the backup station GBZ at Criggion was quickly pressed into service. Some of the usable equipment at Rugby was transferred to Criggion and installed, and within three days, GBZ Criggion was on the air carrying the longwave communication service on behalf of GBR Rugby.
However, it was soon discovered that the results achieved by the new station were found to be far below those of Rugby, and the Admiralty in London expressed great dissatisfaction. The rebuilding of the damaged transmitter at Rugby was therefore given top priority and six months later, the longwave communication service was transferred from GBZ Criggion back to GBR Rugby.
However, from that time onwards, Criggion performed its own meritorious service, on very longwave, longwave and on shortwave, though sometimes widespread flooding from the River Severn made continuous operation quite difficult. Over a period of time, GBZ operated on three different longwave channels 15.2 15.4 & 19.6 kHz.
During the following years, many shortwave transmitters were installed at Criggion, and for example in the late 1940s, a total of 14 different radio circuits were in operation with the corresponding stations in the United States. Twelve of these circuits were arranged with three of the SSB single side band transmitters, and two of these circuits at broadcast quality, were available via the 4th transmitter.
These days, it is no longer known just when and how many radio broadcasts were transmitted from England to the United States from transmitters at GBZ, but it would be presumed that sometimes, when listeners thought they were hearing Rugby, they were actually tuned in to Criggion.
Back around the same era, Criggion operated a relay service on behalf of the new country, Pakistan. Back at the time of partition in 1947, Pakistan found itself divided into two major territories, West Pakistan and East Pakistan, with a thousand miles of India in between. In order to render effective communications between the two new entities, Criggion received and relayed onwards, government communications between the two new regional capital cities, Karachi & Dacca.
During the 1950s, the longwave service with the United States via the Criggion transmitter GBZ was closed down and the service was transferred entirely to Rugby GBR. However, at this stage, the United States exported another longwave transmitter to England where it was installed at Criggion for the navy’s Omega navigation service. Encrypted signals from this 250 kW transmitter we fed into the already existing longwave antenna system.
During the 1970s, 25 shortwave transmitters and the associated antenna systems were removed and scrapped, and several refurbished transmitters from the navy radio station at Waltham were installed. However, with the availability of improved cable communications, and the usage of satellite delivery, Criggion was no longer needed and the station was closed down for ever on March 31, 2003. The remaining useful transmitters were removed and re-installed at Rugby & Ongar, and the remaining communication services were transferred to another transmitting station located at Anthorn.
Criggion can be remembered as a station that underperformed in its original role as a backup station for Rugby, though it did perform its own intended services adequately. There are no known QSLs for any of its communication transmissions, and we would presume that there are none for the few occasions on which it was used for the transfer of radio programming from England to other overseas countries.
(AWR Wavescan NWS 104 via Adrian Peterson)
(photo/some of the towers of the former Criggion VLF Radio/via geograph.org.uk)