Britain's HF Radio Heritage: Bearley
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BT Radio Station Bearley


Image reproduced with kind permission of Ordnance Survey
and
Ordnance Survey of Northern Ireland.

Bearley is a former BT/PO radio station located in Warwickshire, located on the site of the former RAF Snitterfield approximately 5km due north of Stratford Upon Avon. It was a receiver station, being paired primarily with Leafield transmitting station.


Bearley 1950s

Bearley in the 1950's

The site had been used as an HF radio receiving station since the early 1950s and was part of the General Post Office External Telecommunications Executive. In those early days, the accomodation consisted of Nissen huts as seen in the picture above, and the receivers were Marconi GF552 units, which used valves. However, the accomodation was unsuited to the expansion required to meet the demand of the rapidly rising volume of international traffic.

A new station was therefore built at a cost of £0.5 million (equivalent to £6.5 million today) opening in 1967 and which was ‘state of the art’ with new transistorised telephony receivers, the Plessey PVR800. Each RX occupied a full 19 inch rack standing 6ft tall. There were no visible controls except 6 banks of thumbwheel switches to set the channel frequencies. Everything else was managed from a Central Control Unit, CCU.

PVR800 receivers at Bearley

PVR800 Receivers at Bearley

The PVR800 itself was a quadruple-conversion superheterodyne receiver which could be set to any one of 6 preset frequencies or by fully synthesised tuning it could be set to any of the 200,000 available channels in 125Hz increments. The receiver could search for and identify transmissions automatically and once the correct one had been found, it could lock to it and follow variations in the transmitted frequency as long as it stayed within internationally agreed limits.

The receivers used independent sideband which allowed up to 4 voice channels on a single frequency. This was accomplished by splitting each sideband into 2 segments. The audio was also inverted which made it impossible to listen to in an ordinary RX.

The telegraphy receivers were modified Marconi HR11s which again occupied a whole 6ft rack. The heavy bit was the huge PSU at the bottom which provided the HT and heater supplies for the many valves. The HR11s were also controlled from the CCU.

HR11 receivers at Bearley

Marconi HR11 receivers at Bearley

The HR11s looked more like conventional receivers with 2 RF units (double diversity) and a mixer unit each having a large slow motion drive. Converting them to remote control entailed fixing a box containing motors over the space where the knobs for the slow motion used to be. When the operator changed channels there was a loud whirring as the motors moved the dial to one end of travel and then back to the pre-set frequency. Sometimes the automatic system did not quite get things right and manual adjustment was required via a small knob on the motor box.

The HR11 local oscillators had been replaced by frequency synthesisers which allowed pre-set channels to be programmed in. The PVR800 receivers and HR11 synthesisers were locked to a 100Khz standard buried 35ft in the ground for temperature stability. At this depth, the temperature stays within about 0.5° of 10°C all year round without any artificial control. There were three identical standards at the bottom of the wells, at ground level were racks of distribution amplifiers to distribute the standard frequency around the site.

The receivers were located at one end the building and the multiplexing and decoding equipment at the other with the CCU in the centre.

Bearley CCU

The Cenral Control Unit (CCU) at Bearley

The telegraphy side was mostly multiplexed teleprinters using time division multiplex, TDMX. It was possible to get up to 48 channels on a single frequency. There were some TDMX decoders coupled to printers for testing and it was amusing to scan through the channels and watch the printer slow down to a point where each character was taking a few seconds to print.

All the decoded signals were sent down the line to various terminal buildings in London. There were a few racks of line equipment which were often visited by colleagues from PO telephones.

The new station aroused a lot of interest and people from many parts of the world came to visit. There was particular interest in the PVR800 and most visitors seemed to gravitate to the test RX in the maintenance room as there were many problems in the early days. The first models used some germanium transistors which were not particularly reliable and were soon replaced by silicon types.

The Antennas

There was obviously a vast aerial farm and as the station was built on a redundant World War II airfield so space was not a problem. A minor road ran through the site so there were aerials on both sides of the road and the feed lines crossed the road on high poles.

The antennas were nothing special; they were all rhombics at various heights. What was interesting was a ring of rhombics on 75ft wooden poles spaced roughly every 12 degrees of the compass, a radio amateur’s dream antenna system. This feature is even visible on the OS map above.

Antenna Layout at Bearley

The antenna layout

There were also groups of 3 wire rhombics on 150 ft lattice masts and some on experimental designs ion 300 ft masts. Each was fed at both ends meaning they could be used to receive signals from either direction.

Open wire feeders at Bearley

Open wire feeders (left) at Bearley

Each antenna was fed by open wire line supported by standard telegraph poles. The wires came back to a gantry where they connected to broadband transformers and fed using gas filled 75ohm coax into the building via an underground duct. The coax ended up on a patch panel where any RX could be connected to any antenna.

The station closed in 1980 when the last of the HF circuits went over to satellite. So in just 13 years the site went from being state of the art to a pile of junk. There is very little information remaining about Bearley or any of the other stations in the HF network apart from the TX stations at Rugby and Criggion. A search of the Internet for details of the PVR800 will give no hits. Some years back there was one site which showed an unmodified HR11 in a private museum but I guess that receivers in 6ft high 19 inch racks are not going to be collected by many people. It seems that nobody considered that a vital part of our communications history was worth preserving.

After Closure

The BBC World Service broadcast Voice Of America programmes (as well as BBC ones) from Woofferton, under the terms of a contract. Daventry was in need of refurbishment and there was a plan to develop Bearley as a replacement for Daventry. In 1982, the BBC submitted the following planning application:

"EXTERNAL SERVICES HIGH FREQUENCY BROADCAST TRANSMITTING STATION, COMPRISING 6 X 300KW TRANSMITTERS, 30 AERIAL TOWERS OF MAXIMUM HEIGHT 90M ASSOCIATED AERIAL ARRAYS AND FEEDRES(sic) BUILDINGS FOR EQUIPMENT, WORKSHOP STORE"

The application was refused, on the grounds that the high-power transmissions from Bearley would affect the Royal Shakespeare Company's equipment 5 kilometers away in Stratford. As it happens, tests were carried out and it was found that no interference took place, and the planning application was re-submitted the following year in 1983. However, it was refused again.

In the end the whole thing came to nothing because VOA pulled out of Woofferton. As a result, Daventry could be closed and its programme schedule carried by spare capacity at Woofferton and elsewhere.

After 1985, the site appears to have gone into decline with planning applications for the re-use of the land as a golf course being submitted and approved. The part of the site north of Bearley Road is now Stratford Oaks Golf Club, and the part south of that is now a gliding club or else has been returned to agricultural use. There is no visble sign of any original buildings, nor do any masts or mast bases remain.


View Larger Map

Link to Stratford Distrcit Council planning dept search results for Bearley Radio Station. Click on the Planning Applications tab to view all associated applications.

I am indebted to the many people who have contributed to this page. I cannot thank you enough!




Last Modified 16/8/2016, previous 8/10/11, 1/5/10