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kirk o'shotts |
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THE KIRK O'SHOTTS TRANSMITTER broadcasts national and regional DAB radio to the central lowlands of Scotland and is the site of the country's first ever television transmitting station which operated from 1952 to 1985. It is located near Harthill in North Lanarkshire alongside the M8 motorway, approximately fifteen miles east of Glasgow and two miles south-east of the UHF main station at Black Hill. The station was the third of the original four high-power transmitter sites built by the BBC for the primary extension of their 405-line VHF Band I television service beyond London. At its original height, the Kirk o'Shotts mast was identical to those used at the other three stations. It is the only one of these structures that exists today and is consequently the oldest purpose-built stayed television mast in the UK, although it survives only as a result of its interim withdrawal from broadcast service which in turn resulted in its reduction in height upon the removal of the redundant transmission aerials. The station currently transmits DAB radio which it commenced in 1998 after a broadcasting hiatus of over ten years. See STATION HISTORY for more details. |
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STATION HISTORY |
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405-LINE TELEVISION |
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The Kirk o'Shotts transmitter was constructed by the BBC to extend their 405-line VHF Band I television service to Central Scotland, bringing within range a further four million people who mainly resided in or around Glasgow and Edinburgh. Having established two provincial high power transmitters at Sutton Coldfield and Holme Moss in 1949 and 1951 respectively, Kirk o'Shotts was the third of the four stations required as the foundation of a UK-wide BBC VHF transmitter network. In the initial BBC assessment of possible sites for a Scottish transmitter, one of the proposals was to co-site with the existing BBC medium and long-wave (AM) station at Westerglen (eight miles north of Kirk o'Shotts) but this was quickly dismissed on the grounds of low site elevation and possible mutual interference with the AM services. The BBC then looked at two possible locations for a single high-power transmitter, one was Kirk o'Shotts, the other was Hendrey's Course, near Bathgate. Whilst the latter site was fairly comparable in its estimated coverage, it had the disadvantage of remoteness, being detached by some practical distance from the nearest road as well as utilities, whilst Kirk o'Shotts was near to all these and on a plateau that was easier to build on. At this stage, however, these were just land assessments with full testing still to take place. In the belief that coverage in outer areas like Dundee in the north-east and Ayrshire in the south-west would be inadequate from a single transmitter, the BBC considered the option of separate lower power stations respectively based near Glasgow and Edinburgh. The two sites looked at were Ballageich Hill (near Paisley) for the Glasgow site and Clatto Hill (near Cupar, Fife) for Edinburgh, both of which were also expected to offer better coverage to the main cities as well as the outlying areas. However, once full testing from the Kirk o'Shotts site was completed, this revealed overall results far better than anticipated, with sufficient coverage across the main centres and Ayrshire, whilst the Lomond Hills (the area of the Clatto Hill site) proved less of a hindrance than predicted in delivering an adequate service to Dundee. The station was also deemed a suitable location for the transmission of BBC National Radio on FM VHF Band II as was the case at the other high-power sites, the corporation wanting to co-site both Band I and Band II transmission to save costs. The station was therefore approved once all other enquiries, including checks related to historic mining activity, had been satisfactorily concluded. The 228 metre (750-ft) mast at Kirk o'Shotts maintained the design implemented at Sutton Coldfield and Holme Moss and later at Wenvoe, comprising a lower lattice triangular cross-section up to a height of 186 metre (610-ft), followed by a 32 metre (105-ft) cylindrical steel slotted section for VHF Band II aerials, topped with a final 10 metre (35-ft) lattice spine for carriage of the Band I television aerial. In addition to common aesthetic features which also included the station building, another detail applicable to all four stations was the maximum Effective Radiated Power (e.r.p) which was set at 100kW (Band I) and 120kW (Band II). Broadcasting on VHF Channel 3, Kirk o'Shotts commenced transmission on 14 March 1952, operating initially at reduced power from reserve transmitters until the main high power transmitter came into service on 17 August 1952. This was capable of delivering a maximum actual power of 70kW but in practice operated at 50kW in order to achieve the maximum allocated e.r.p of 100kW based on the low gain aerial principle that applied until Crystal Palace in 1956. The station received its main in-coming programme feed from London which was mainly line-fed as far as Holme Moss and then continued from there on a GPO 4 GHz microwave link with relay points including a forwarding station at Pontop Pike, close to the BBC transmitter opened there in 1953. The BBC extended their Scottish television coverage by linking the service area of Kirk o'Shotts with Aberdeenshire with the opening of the medium-power transmitter at Meldrum from 13 October 1955. Further stations at Rosemarkie (Inverness) and Thrumster (Caithness) extended coverage to the far north of mainland Scotland, with yet more stations (including Orkney) built built to serve the Scottish Islands. Later entries into the network included the Ashkirk transmitter which improved Kirk o'Shotts reception across hill-screened areas of the Scottish Borders, whilst the Forfar station in conjunction with a relay at Dundee Law improved the service around Dundee itself and the county of Angus. A number of relays were also built along the Ayrshire coast in areas where reception was revealed to be poor. |
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BBC NATIONAL FM RADIO |
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Transmission of BBC National FM Radio services commenced from Kirk o'Shotts on 30 November 1957. As per Sutton Coldfield and Holme Moss, the four-sided horizontally polarised aerials were vertically-aligned with the lowest eight tiers of the ten-tier mast cylinder. The allocated frequencies were 89.9MHz (Light Programme), 92.1MHz (Third Programme) and 94.3MHz (Home Service). |
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UHF AND MAINTENANCE OPERATIONS |
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The ITA Band III 405-line transmitter for Central Scotland had come into operation at Black Hill on 31 August 1957, having been intentionally built near to Kirk O'Shotts in accordance with the established practice of adjacent siting. When it came to location choice for co-siting BBC and ITA 625-line UHF-colour transmitters, Black Hill was the preferred option due mainly to the 306-metre (1002-ft) mast. UHF transmissions from here commenced with BBC2 on 9 July 1966. In 1975, Kirk o'Shotts became the regional base for the new Monitoring and Information Centre (MIC), the first of five to be established nationwide. From here, faults occuring across the substantially increased network of transmitters (resulting from the change to UHF) could be identified and diagnosed remotely from the control desk. Aided also by more reliable solid-state technology at the transmitters, this reduced the need for on-site attendance by the Transmitter Maintenance Teams (TMTs). The Kirk o'Shotts MIC eventually covered both Scotland and Northern Ireland. This next to open was Wenvoe in 1978, followed by further centres at Crystal Palace, Holme Moss and Sutton Coldfield. |
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SERVICE CLOSURE |
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In 1980, the UK government confirmed that 405-line television would close completely by 1986 (later brought forward to January 1985) whilst in the same year the BBC announced plans to upgrade transmission of their FM radio service to mixed polarisation. From the engineering perspective, the BBC would combine the decommissioning of the former and the upgrade for the latter into one large-scale modernisation project. All four of the original high-power Band I sites were listed for refurbishment but a new FM aerial system with both horizontal and vertical components meant a larger and bulkier installation that would not only place a significant weight burden on these earliest BBC-TV masts, but would also be impossible to mount inside or around the integral Band II cylindrical slot section. For these first generation sites, the only way forward was replacement masts and these were constructed at Sutton Coldfield, Wenvoe and Holme Moss between 1983 and 1986. At Kirk o'Shotts however it was decided not to replace the mast and instead relocate the remaining (post-405 closure) FM services to Black Hill, with personnel and operations ultimately moving across as well. The definitive reasons for this are unconfirmed but what is certain is that new masts were essential at Sutton Coldfield and Wenvoe as they had become UHF main stations whilst Holme Moss, although not chosen for UHF, remained a prime location for VHF radio transmission. Kirk o'Shotts however had no logistical advantages and was neighbouring a UHF main station that was suitably equipped and positioned to transmit the BBC FM services. Once FM transmissions from Kirk o'Shotts were relocated, the entire cylindrical slot segment and surmounting Band I aerial were removed from the mast, leaving only the main lattice triangular cross-section in place. This reduced the mast height to 183 metres (600-ft), the redundancy of the site the cause of its truncation but ironically also the reason for its survival, although the reduction starkly symbolised the station's obselescence. The mast was nevertheless retained in this diminished form to allow for other uses, such as SHF links and commercial tenants, plus for future broadcast use if needed. The site remained part of the BBC estate and of its private sector successors although, based on signage present, the site was managed for a period by mobile services company Dolphin UK, who later went into administration. |
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DAB RADIO |
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Kirk o'Shotts did resume broadcasting on 18 February 1998 with the commencement of BBC National DAB radio transmission. For this, a DAB transmitting aerial was installed at the top of the mast where the former Band II FM cylinder section commenced. Two further DAB multiplexes were added soon after, Digital One from 5 October 1999 and Central Scotland from 31 May 2001, with these remaining the current services from the station. |
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SITE IMAGES |
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(Larger versions on Landscape Enlargements page) Although the station's history is not immediately obvious on approach, a closer view reveals the familiar building design used at other early BBC transmitting stations. The BBC Crest that would have been positioned above the main entrance has been removed to a location unknown, although one possibility is that it is now at Black Hill. |
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SITE INFORMATION |
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Location: |
Forrest Road, Kirk of Shotts, Harthill, North Lanarkshire |
Grid Reference: |
NS858636 |
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Landlord: |
Arqiva (Legacy: BBC/Crown Castle/NGW) |
Ground Height: |
277.4m |
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BBC Region: |
N/A |
Mast Height: |
183m |
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ITV Region: |
N/A |
Aerial Height: (*) |
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UHF Tx Number: |
N/A |
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CURRENT TRANSMISSIONS |
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Digital Television |
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Analogue Radio (FM) |
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Service |
: Ch/Polarisation/e.r.p |
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Service: |
(MHz) |
(e.r.p) |
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No service - transmitted from Black Hill |
No service - transmitted from Black Hill |
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Digital Radio |
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BBC National (Block 12B) |
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Digital One (Block 12A) |
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Switch Scotland (Block 11D) |
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