Emley Moor
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  Map sources for Emley Moor at grid reference SE222128
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Emley Moor is an area of moorland near the village of Emley, near Huddersfield in West Yorkshire, England (national grid reference: SE222128).
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[edit] History
The current tower is the third structure to have occupied the site. The original 135 m (445 ft) tower was erected in 1956 to provide independent television broadcasts to the Yorkshire area. It was replaced in 1964 by a taller 385 m (1265 ft) guyed mast (identical to the structure still standing at Belmont).
[edit] Tower collapse
Emley Moor has been used as a transmission site since the earliest days of TV transmission. The first permanent transmitter to be built there was an ITV transmitter, covering much of the North. However, this service used a 135 metre tower, limiting coverage. The performance of the site was improved in 1966, in anticipation of PAL transmissions, when a 385 metre guy-supported tubular mast was erected, constructed from curved steel segments to form a 2.75 metre diameter tube, 275 metres long. This was surmounted by a lattice section 107 metres tall and a capping cylinder, bringing the total height to 386 metres. At the time of its construction, it was one of the tallest standing structures in the world. It was designed by BICC and manufactured by EMI.
The cylindrical steel mast regularly became coated in ice during the winter months, and ice also formed in large icicles on the guy ropes, placing them under considerably greater strain. The guy wires passed over several small roads, and thawing ice caused a falling icicle hazard. For this reason, red warning lights were placed on the tower for use in times of falling ice, with notices posted on the roads near the guy crossings.
On 19 March 1969, a combination of strong winds and the weight of ice that had formed around the top of the mast and on the guys brought the structure down. The Duty Engineer wrote the following in the station's log book, demonstrating that this failure of the structure was completely unexpected:
- Day: Lee, Caffell, Vander Byl
- Ice hazard - Packed ice beginning to fall from mast & stays. Roads close to station temporarily closed by Councils. Please notify councils when roads are safe (!)
- Pye monitor - no frame lock - V10 replaced (low ins). Monitor overheating due to fan choked up with dust- cleaned out, motor lubricated and fan blades reset.
- Evening :- Glendenning, Bottom, Redgrove
- 1265ft Mast :- Fell down across Jagger Lane (corner of Common Lane) at 17:01:45. Police, I.T.A. HQ, R.O., etc., all notified.
- Mast Power Isolator :- Fuses removed & isolator locked in the "OFF" position. All isolators in basement feeding mast stump also switched off. Dehydrators & TXs switched off.
The collapse left sections of twisted mast strewn across the surroundings of the transmitter site and across several small local roads. Although one of the falling stay cables cut through a local church and wreckage was scattered all over the transmitter site, nobody was hurt in the collapse. The noise was reportedly heard for several miles. The collapse, of course, completely disabled the UHF transmitter, leaving several million people without service on their modern UHF-only sets. VHF services continued from the smaller 135 metre mast. The ITA owned a collapsible emergency mast, 61 metres tall, and it was quickly moved to Emley so that some service could be restored. ITV signals were restored to 2.5 million viewers within only four days. The BBC provided a mobile mast on an outside broadcast van, which was used to restore a restricted BBC2 colour service within just two days. The ITA bought a larger temporary mast from a Swedish company. A crew of Polish riggers were hired and a 204 metre mast was erected in just under 28 days at a cost of £100 000. However, this mast was only capable of holding one set of antennae, so many viewers in outlying areas still could not receive colour programmes. The taller mast was brought into service on April 16th. Some weeks later, the BBC erected a 91 metre mast, improving coverage.
The accumulation of ice was generally believed to have caused the collapse, but a committee of inquiry attributed it to a form of oscillation which occurred at a low but steady wind speed. Modifications were then made to similar masts at Belmont and Winter Hill, including the hanging of fifty tons of steel chains within each structure. None of the modified masts have collapsed.
After a series of temporary masts, erection of the current concrete-built tower began in 1969 with UHF (625-line colour) transmissions commencing on 21 January 1971 with the older VHF (405-line black & white) system coming into operation on 21 April 1971. Local residents did not wish to see another mast on Emley Moor, and so a departure from normal designs was called for. The new structure consists of a curved pillar, 275 metres tall, constructed of prestressed concrete, topped by a 55 metre steel lattice mast which carries the antennae.
[edit] The Structure
The structure is a tapered, reinforced concrete tower. It is the tallest freestanding structure on the British Isles at a height of 330.4 metres (1084 feet). Reaching the Tower Room (at the top of the concrete part of the tower at 275 m (900 ft) involves a seven-minute journey by lift. The antenna structure above this is a further 56 m (184 ft). Its foundations penetrate 6.1 m (20 ft) into the ground and the whole structure, including foundations, weighs 11,200 tonnes. It was designed by Ove Arup and Partners. When it was built, it was the tallest man-made structure in Europe.
The UK Government declared Emley Tower a Grade II Listed Building of 'significant architectural or historic interest' in 2002.
[edit] Ownership
It is owned by Arqiva. Previous owners have been the Independent Broadcasting Authority and NTL.
[edit] Broadcast details
The Emley Moor tower broadcasts BBC One, BBC Two, ITV1 Yorkshire, Channel 4, Five, six digital television multiplexes, three digital radio ensembles and two independent local radio stations (Galaxy 105 and Real Radio) over an area of approximately 10,000 km². It is the main station for some 57 relays and repeaters throughout Yorkshire and surrounding counties.
[edit] Repairs and Alterations
Over the years, the structure has been updated with various dishes and aerials. This reflects the changing nature of communications and technology. The most visible changes are on the outside of the tower. At both the top and bottom of the tower, further supporting structures have been attached to accommodate the dishes and aerials.
The BBC reported in July 2006 that for up to two weeks, the tower was liable to broadcast analogue and digital signals at a lower power than usual, or be shut down between 0900 and 1500 BST on weekdays in late July until the 4 August. This is to allow aircraft warning lights to be fitted to the tower and repairs to be carried out. The repair work was estimated to affect around five million homes; however, a spokesperson for National Grid Wireless announced that the work had been scheduled around major events. [1]
[edit] Other Structures of Comparable height
- This is taller than One Canada Square (Canary Wharf), Britain's tallest building, which is only 235 m (771 ft) high.
- The Belmont mast in Lincolnshire, which is a guyed mast is 385 m (1265 ft) high, making it the tallest structure of any kind in the country.
- The Eiffel Tower is 300 m (984 ft) high, with an additional 24m (79 ft) antenna on top.
[edit] Viewing the tower
The tower is not open to the general public. However, there is an observation area just off the main road that runs past it. This provides an excellent view of the structure.
[edit] Trivia
- The top of the current tower at Emley Moor is 594 m (1949 ft) above sea level due to the site's elevated position on the Eastern edge of the Pennines.
- This area has always been important for RF (Radio Frequency) transmission and from the foot of Emley's structure both Holme Moss and the Moorside Edge Transmitter are visible. Both of the latter are within 10 miles radius and are SW and WNW respectively.
- The tower can be seen from the M1 motorway (between Woolley Edge services and junction 38).
- Poet Simon Armitage wrote a poem about Emley Moor, to accompany a short programme about the tower on BBC2 in the 1990's.
[edit] Channels listed by Frequency
- Digital Radio (DAB)
- Block 11D: 222.064 MHz — Digital One
- Block 12A: 223.930 MHz — MXR Yorkshire
- Block 12B: 225.648 MHz — BBC
- Analogue Television
- Digital Television
- UHF 40 (626 MHz) — Multiplex 2 Digital 3&4
- UHF 43 (650 MHz) — Multiplex A SDN
- UHF 46 (674 MHz) — Multiplex B BBC
- UHF 49 (698 MHz) — Multiplex D National Grid Wireless
- UHF 50 (706 MHz) — Multiplex C National Grid Wireless
- UHF 52 (722 MHz) — Multiplex 1 BBC
[edit] See also
- Telecommunications in the United Kingdom
- Radio masts and towers
- Radio masts and towers - catastrophic collapses
- List of tallest buildings and structures in Great Britain
- List of towers
- List of masts
- List of radio stations in the United Kingdom
[edit] External links
- MB21 Transmission Gallery, Emley Moor index.
- Info and pictures of Emley Moor including co-receivable transmitters
- TV Tower Emley Moor.
- Diagram of the NTL Tower.
- Views of Emley Moor mast from Anoraks Guide to Radio in North Yorkshire.
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| Antennas: | Alma-Ata Tower, Azeri TV Tower, Emley Moor, Europaturm, Gerbrandy Tower, Kiev TV Tower, Mumbai Television Tower, Saint Petersburg TV Tower, Sumida Tower (proposed), TV Tower Yerevan, WITI TV Tower, Zendstation Smilde |
| Bridges: | Millau Viaduct, Strait of Messina Bridge (proposed) |
| Dams: | Rogun Dam (construction), Nurek Dam, Jinping 1 Hydropower Station (construction) |
| Solar towers: | Solar Tower Buronga (proposed), Ciudad Real Torre Solar (proposed) |
| Electricity pylons: | Yangtze River Crossing |
| Oil platforms: | Petronius Platform, Baldpate Platform, Bullwinkle Platform, Troll Platform, Gullfaks C |
Categories: Articles to be expanded | Cleanup from August 2006 | All pages needing cleanup | 1964 establishments | 1969 disestablishments | 1971 establishments | Demolished buildings and structures | Destroyed landmarks | West Yorkshire | Grade II listed buildings | UK transmitter sites | Towers in the United Kingdom
