Westerglen

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Westerglen is a medium and long-wave transmitting station located a few miles south-west of Falkirk, serving the population of central Scotland. Opened on 2 May 1932, it was originally the site of the BBC's third 'twin-wave' transmitting station, which for the first time allowed two programme services to be radiated to Scotland simultaneously and over a much larger area than before. It currently transmits BBC Radio Scotland (810 kHz), BBC Radio 5 live (909 kHz), Absolute Radio (1215 kHz) and talkSPORT (1089 kHz) on medium wave, and is one of only three stations in the UK to transmit BBC Radio 4 on long wave (198 kHz)

Rationale

In the late 1920s, the BBC was keen both to extend wireless to new areas, but also offer listeners a choice of listening. With just ten wavelengths allocated to Britain under international agreement, the BBC's options were limited, and so it was decided to create five 'twin-wave stations' at strategic locations throughout the country.

In order to maximise their reach, the Regional transmitters were built on higher ground but, unlike their local predecessors, were to be found in remote areas far outside city centres. This was because anyone living in close proximity to these high-powered transmitters would likely find their reception of alternative stations all but 'drowned out'. This was particularly a problem for owners of crystal sets which, due to their lack of amplification, were dependent upon the very minute currents picked up by their aerials. It was only with more sophisticated, and expensive, valve sets that good 'selectivity' was possible.

The experimental station at Daventry (Midland Region) opened on ???; Brookmans Park (London) on 9 March 1930; Moorside Edge (North Region) on 12 July 1931; Westerglen (Scottish Region); Washford Cross (West & Welsh Region) in August 1933.

The transmitters radiated two separate services: the National Programme allowed those who wanted to hear London output to do so without local interruptions; while those who actively craved more indigenous culture had their respective Regional Programme.

As well as being of much higher power than the city-based transmitters it replaced, the new technology at Westerglen was capable of transmitting music much more realistically.

Development

"Population density map 1932"

On 14 June 1928 the BBC wrote to the General Post Office requesting permission to proceed immediately with the erection of twin wave high-power transmitters at Glasgow, Manchester and Cardiff, and a single wave high-power station at Belfast. On 19 July 1928, the GPO wrote back granting its approval.[1]

The BBC decided that the best location for its Scottish Regional transmitter would be in central Scotland where 80 per cent of the nation's population lived. In August 1930, after months of survey work using a portable transmitter on a lorry, it decided on a spot at Wester Glen, three miles south-west of Falkirk on the Falkirk-Slamannan Road. At 500 feet above sea level it was the favourite of three sites tested. The second potential site at Grangemouth Road was situated at sea level and had any difficulty been experienced at Wester Glen it would have been suitable. The third site at Hope Farm, Bonnybridge, was 250 feet above sea level, but did not meet with the requirements of the testing engineers. The specifications were to be for two buildings of one storey each, and a staff of about 40 engineers resident in the district.[2]

The Governors subsequently agreed to accept the tender of the Anglo-Scottish Construction Company for the erection of the building works at a total cost of £47,756.[3] Anglo-Scottish had already built the London Regional transmitter at Brookman's Park, and the North Regional transmitter at Moorside Edge, near Huddersfield. Westerglen would be similar in layout, but with some improvements. The building work was completed by the end of 1931. A separate contract was signed with the Radio Communication Company for the supply and erection of two 500ft lattice steel masts at a cost of £8,950.[4]

The total cost of the project, including buildings and equipment, was around £200,000.[5] Mr Robert Bird was the engineer in charge of the station.

Configuration

A description of Westerglen was published in the press a few weeks before the transmitter's official opening.[6] Westerglen closely followed the design of the earlier London Regional Station at Brookmans Park and the North Regional Station at Moorside Edge, near Huddersfield. However, the arrangement of the aerial system was quite different.

Aerials

At Brookmans Park, the BBC was limited by Government regulations to a mast height of 200 feet, and two masts supported each of the two aerials. At Moorside Edge no restrictions were imposed and three masts each 500 feet high and built in triangular formation support the two aerials. In view of the shorter wavelengths to be employed at the Scottish Station, and the desirability of adopting the cheapest mast arrangement consistent with efficient working conditions, a series of experiments were carried out to determine the suitability of a type of "umbrella" aerial which required only one mast to support it. The experiments were successful and this type of aerial was accordingly adopted for the Scottish station.

The set-up consisted of two triangular stayed lattice steel masts, each 502 feet high and visible from many miles away. Owing to their height, red lights were fixed at the top to give warning after dark to aircraft. Each mast supported three radiating conductors suspended from the top at equal distances in the form of an umbrella, and held at the bottom by anchorages attached to a concrete block approximately 150 feet from the base of the mast. The three wires were brought together in an aerial transformer house situated at the foot of the mast. This building contained the high-frequency circuits necessary to transfer the energy from the incoming high-frequency feeder lines to the aerial. The masts were insulated from earth to withstand a pressure of 10,000 volts.[7]

The battery room

The power for the station was generated from crude oil by means of four diesel engines directly coupled to direct current generators. Three months' supply of fuel oil was stored in two tanks, each of 75 tons capacity, at the rear of the building. The engines and generators were all mounted on a foundation weighing 600 tons, which in turn rested on cork to prevent vibration from being communicated to the other apparatus in the building.

The whole building was heated by waste heat extracted from the exhaust gases of the diesel engines, but an auxiliary oil-fired boiler was used when the diesels were not running.

The main battery storage consisted of 115 cells of 2000 amperes capacity at a 10-hour discharge rate. This battery was intended to take the load of one generating set for one hour in the even of the sudden failure of an engine or generator; to supply power for lighting etc. when the diesel engines were not running; to assist in maintaining a constant voltage; and to enable the diesel engines to be run under full load, which was the condition of highest efficiency.

The machine room

The power was generated at 230 volts, direct current. It was, of course, necessary to convert the power at different pressures for the various inputs to the transmitter. For example, the transmitter required a direct current high tension supply of 12,000 volts for the anodes of the power valves, and a low tension supply at 20 volts for the filaments in its power valves. In addition, the transmitter required high tension for its early stages of amplification, grid bias etc.

The power supply was converted from the power house by means of motor generators. These consisted essentially of direct current motors driven from the main power supply of 230 volts, which in turn drove generators delivering power at the various pressures required.

Transmitter hall

The transmitter hall was similar in layout to the London and North Regional stations. The two transmitters were arranged down either side of the hall, the 'National' transmitter being on the left as one entered from the front entrance. Each transmitter had its own control desk, which was situated in front of the unit containing the tuning circuits. As the magazine Passing Show described it: "Inside the spacious transmitter hall tall rows of water-cooled valves glow a dull crimson as they pump the National and the Scottish Regional programmes out into the ether."[8]

The hall was lighted through a dome in the roof instead of through windows in the walls, as in the previously-constructed London and North Regional stations. This arrangement reduced dazzle and eye-strain to the engineers when reading meters.

Each complete transmitter consisted of five cubicles or units built-up on an aluminium framework with glass panelled doors in front, and metal panels or doors at the sides and back. As in the London and North Regional transmitters, all the doors of each cubicle were locked by the movement of a single handle from the front. When this handle was moved to unlock the doors, all current supplies were automatically cut-off and could not be reconnected until all the doors were closed properly, and the handle moved to the 'on' position.

Front of building

The front portion of the building had two storeys — the ground floor containing two control rooms, test room, and a room to house tuning fork apparatus, and offices; and the upper floor containing a studio, quality-checking room and domestic offices.

The studio was used chiefly for testing purposes, although it could also be used in emergency for announcements or ordinary transmissions, including the broadcasting of gramophone records.

The test room contained apparatus suitable for checking the performance of the transmitters, including a variable tone source, a special relaying receiver, and cathode ray oscillograph.

The control rooms contained the terminal points of the land lines connecting the transmitter to the Regional headquarters in Edinburgh, and also modulation meters, check wireless receivers, line testing and other equipment necessary for the monitoring of programmes.

Launch

In order to give listeners an opportunity to accustom themselves to the new wavelengths and make any adjustments required to their receivers, the service was transferred gradually.

The first test transmissions on the Scottish Regional Programme wavelength of 376.4m took place on 2 May 1932, radiating mornings and nights outside of normal programme hours.

Then from Monday 23 May, the National Programme was broadcast on this wavelength from 10.15 am until midday and 10.30 pm until midnight.[9]

The full regular Scottish Regional Programme service was officially launched on 12 June 1932. On this date the old city-based transmitters in Glasgow, Edinburgh and Dundee were closed down (they stood by for a time in case of breakdown at Westerglen but were then dismantled).[10]

The second, alternative service, the Scottish National Programme began public test transmissions on 22 August 1932, with the full service officially launched on 25 September 1932.

Service area

At a strength of 50 kilowatts, the Scottish Regional Programme transmitter, broadcasting on a wavelength of 376.4m (767kc/s), was designed to radiate a signal approximately 70–80 miles in all directions from Falkirk — the maximum range in which a consistently reliable service could be given. The National Programme transmitter, broadcasting on a shorter wavelength of 288.5m, was expected to radiate a reliable signal at a distance of 50–60 miles.[11] The latter also shared its wavelength with other National Programme transmitters across the country.

This arrangement took-in 80 per cent of the population of Scotland (a large proportion of the remainder was served by the Aberdeen transmitter, which remained in service). Compared to the city-based transmitters they were replacing, the new Regional transmitters brought an additional one million listeners into a 'good service area'.[12]

While reception after dark was possible over a much larger area than before, some unavoidable fading was experienced by listeners outside the service area defined.

By 1936 the transmitters were working unofficially at 75kW and this was to be raised to 100kW.[13]

Thunder and lightning storms

If affected by even a slight lightning charge, the transmitters would automatically close down for a short period. Sometimes they would be manually turned off as a precautionary measure, such as on 4 August 1936 when a thunder and lightning storm in the Falkirk area saw both the National and Regional transmitters closed down for around 15 minutes.[14]

Key dates

  • 12 June 1932 — Scottish Regional Programme officially enters service on 797 kHz; former local transmitters closed at Glasgow, Edinburgh and Dundee.
  • 25 September 1932 — National Programme enters service on 1040 kHz.
  • 15 January 1934 — frequencies changed to Scottish, 804 kHz, National, 1050 kHz.
  • 17 February 1935 — Scottish Regional frequency changed to 767 kHz.
  • 4 July 1937 — National Programme frequency changed to 1149 kHz.
  • 1 September 1939 — National Programme, 1149 kHz closed. Scottish Regional, 767 kHz replaced by the Home Service.
  • 29 July 1945 — 767 kHz becomes Scottish Home Service. Light Programme launched on 1149 kHz.
  • 15 March 1950 — Frequencies changed to Scottish Home Service, 809 kHz, Light Programme 1214 kHz.
  • 30 September 1967 — 1214 kHz re-assigned to Radio 1; Scottish Home Service becomes 'Radio 4 (Scotland)'.
  • 23 November 1978 — Radio Scotland frequency changed to 810 kHz; 1214 kHz changed to 1215 kHz and re-assigned to Radio 3. New transmitters brought into service for Radio 1 (1089 kHz), Radio 2 (909 kHz) and Radio 4 (200 kHz).
  • 1 February 1988 — Radio 4 frequency changed to 198 kHz.
  • In the 1990's, 909 kHz becomes Radio 5, 1215 kHz, INR 2 (Virgin Radio) and 1089 kHz, INR 3 (Talk Radio).

Wavelengths and frequencies

Date Scottish Regional Scottish National Comments
Frequency (kc/s) Wavelength (m) Frequency (kc/s) Wavelength (m)
2 May 1932 797 376.4 288.5 Radio Times
15 Jan 1934 804 373.1 1050 285.7 Outcome of Lucerne wavelength plan[15]
17 Feb 1935 767 301.1? n/a n/a Rearrangement of British wavelengths to improve service; co-inciding with the opening of Droitwich LW station.[16]
July 1937? 1149 261.1 Synchronised with the London and North National Programme transmitters (also on 261.1m) to enable listeners in south and south-west England to have a separate regional programme from Wales. Change also improved reception in south-west Scotland.[17]
March 1940 380.2 262.9 Result of the Montreux Conference of 1939.[18]

Post-Second World War

Date Scottish Home Service / Radio 4 Light Programme / Radio 1 Third Programme Comments
Frequency (kc/s) Wavelength (m) Frequency (kc/s) Wavelength (m) Frequency (kc/s) Wavelength (m)
29 July, 1945 767 391.1 1149 261.1 n/a n/a To prevent interference with the North regional transmitter, which sent out the Light Programme on the same wavelength, Westerglen's Light aerial had special directional qualities so that its radiation to the east and west was strengthened, and to the north and south it was weakened.[19]
15 March, 1950 809 370.8 1214 247.1 n/a n/a Changes as a result of the Copenhagen Plan; power increased from 60 to 100kW (max allowed under Copenhagen Plan).
30 Sept 1967 Radio 4 (Scotland) Radio 1 Comments
809 371 1214 247 n/a n/a Scottish Home Service becomes Radio 4; Light Programme becomes Radio 1.
23 November 1978 BBC Radio Scotland BBC Radio 3 Other
810 370 1215 (Radio 3) ? n/a n/a Geneva Plan

References

  1. Minutes of Board of Governors Meeting, 25 July 1928, BBC WAC R1/1/1.
  2. 'New regional station at Falkirk', Glasgow Herald, 26 August 1930, 9.
  3. Minutes of Board of Governors Meeting, 17 September 1930, BBC WAC R1/1/1.
  4. Contract was signed on 15 June 1931. See 'Minutes of board meeting', 24 February 1932, BBC WAC R1/2/1.
  5. 'Scotland Calling', Scotsman, 21 May 1932, 17.
  6. 'Wireless in Scotland: new regional transmitter at Falkirk', Glasgow Herald, 21 May 1932, 3.
  7. BBC Year Book 1933, 235–6.
  8. 'Radio's mountain stronghold', Passing Show, 4 July 1936.
  9. 'Scotland Calling', Scotsman, 21 May 1932, 17.
  10. 'Broadcasting in Scotland', Glasgow Herald, 11 June 1936, 10.
  11. 'The new regional station: first public tests', Glasgow Herald, 3 May 1932, 10.
  12. ‘Radio exhibition in Glasgow’, Glasgow Herald, 29 September 1932, 3.
  13. Sunday Referee, 8 March 1936.
  14. 'Scottish wireless programmes: interrupted during thunderstorm', Glasgow Herald, 5 August 1936, 11.
  15. 'Change of frequencies and wavelengths', Glasgow Herald, 22 November 1933, 10.
  16. 'Wireless wavelengths: change for Scottish station', Glasgow Herald, 29 January 1935, 6.
  17. 'Broadcasting in Scotland: transmission changes announced', Glasgow Herald, 19 January 1937, 6.
  18. 'New wavelength plan', Glasgow Herald, 18 April 1939, 2.
  19. Speech by Sir Edward Appleton, 'Radio-Communication', 3 May 1949, BBC WAC R44/118.