Emley Moor

Emley Moor is an area of moorland in the village of Emley, in Kirklees, West Yorkshire, England (national grid reference: SE2219712899), and also the name of a supertall telecommunications and broadcasting station on the site. The tower, which is a Grade II listed building, is the tallest freestanding structure in the United Kingdom, 7th tallest freestanding structure in the European Union, 4th tallest tower in the European Union, and 25th tallest tower in the world (see List of towers).


History

The current tower is the third structure to have occupied the site. The original 135 metres (443 ft) lattice tower was erected in 1956 to provide Independent Television broadcasts to the Yorkshire area. The mast entered service on 3 November 1956, carrying the programmes of Granada TV (weekdays) and ABC TV (weekends). It was replaced in 1964 by a taller 385.5 metres (1,265 ft) guyed mast (identical to the structure still standing at Belmont in Lincolnshire). The dismantled lattice tower was rebuilt at Craigkelly transmitting station.


Mast 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. It used a 135 metre lattice tower, which provided only limited coverage. The performance of the site was improved in 1966, in anticipation of colour PAL transmissions, when a 385 metre guy-supported tubular mast was erected, constructed from curved steel segments to form a 2.75 metres (9 ft) diameter tube, 275 metres (902 ft) long. This was surmounted by a lattice section 107 metres tall and a capping cylinder, bringing the total height to 386 metres (1,266 ft). 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 wires, 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 wire 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 guy wires 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:


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 completely disabled the BBC2 UHF transmitter and the ITV VHF transmitter, leaving several million people without service. BBC1 VHF Television transmissions continued from the nearby Holme Moss transmitter. The ITA owned a collapsible emergency mast, 61 metres tall, and it was quickly moved to Emley from the ITA transmitter at Lichfield 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, with Jozef Miciak in charge, were hired and a 204 metre mast was erected in just under 28 days at a cost of £100,000. However, this mast could hold only one set of antennas, so many viewers in outlying areas still could not receive colour programmes. The taller mast was brought into service on 16 April. 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 150 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 reinforced concrete, topped by a 55 metre steel lattice mast which carries the antennas.


A section of the collapsed tower was converted for use as a racing control tower at nearby Huddersfield Sailing Club.


The structure

The structure is a tapered, reinforced concrete tower. It is the tallest freestanding structure in the United Kingdom at a height of 1,084 feet (330 m). Reaching the Tower Room at the top of the concrete part of the tower at 900 feet (274 m) involves a seven-minute journey by lift. The antenna structure above this is a further 184 feet (56 m). Its foundations penetrate 20 feet (6 m) 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 third-tallest freestanding structure in Europe, after the Ostankino Tower at 1,772 feet (540 m) and the Fernsehturm Berlin (current height 1,207 feet (368 m).


The top of the tower is 1,949 feet (594 m) above sea level due to the site's elevated position on the Eastern edge of the Pennines.


In 2002, the UK Government declared Emley Tower a Grade II Listed Building of 'significant architectural or historic interest'.


Ownership

It is owned by Arqiva, previously the Independent Broadcasting Authority Engineering privatised as NTL Broadcast.


Broadcast details

The Emley Moor tower broadcasts BBC One, BBC Two, ITV1 Yorkshire, Channel 4, Channel 5, six digital television multiplexes, three digital radio ensembles and two independent local radio stations (105 Capital FM & Real Radio) over an area of approximately 10,000 km². It is the main station for some 57 relays and repeaters throughout Yorkshire and the surrounding counties. In July 2007 it was confirmed by Ofcom that Emley Moor would be remaining a B group transmitter after DSO (Digital Switchover).


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 these are within ten miles (16 km) radius and are SW and WNW respectively.


The television coverage area covers one of the largest areas in the UK; covering most of Yorkshire including Hull, Leeds, and Sheffield. Some transmissions can also be received in Greater Manchester across the Pennines due to the height of the transmitter and the strong signal strength.


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 to be shut down between 0900 and 1500 BST on weekdays in late July until the 4 August. This was 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.


Digital UK reported in April 2010 that the transmitter would undergo works in preparation for the digital switchover in 2011. The disruption to some or all Freeview services was expected to last for around two months, during which time a reserve transmitter would continue to broadcast the 5 main analogue channels. The work was then reported to be continuing into September due to "poor weather conditions and complex engineering issues".


Digital switchover

BBC Two analogue will cease transmissions on 7 September 2011. The remaining four analogue services will follow on 21 September 2011, with the digital multiplexes given a power increase.


Viewing the tower

The tower is not open to the general public. There is an observation area just off the main road that runs past it.


In popular culture

  • Poet Simon Armitage wrote a poem about Emley Moor to accompany a short programme about the tower on BBC2 in the 1990s.

Channels listed by frequency

Analogue radio (FM)

Digital radio (DAB)

Analogue television

Digital television (DVB-T/DVB-T2)

Other structures of comparable height

  • Emley Moor will be 20 metres (66 ft) taller than the Shard London Bridge tower, which will be tallest building in the UK when it's completed in 2012.
  • It is 95 metres (312 ft) taller than One Canada Square (Canary Wharf), Britain's second tallest building, which is 235 metres (771 ft) high.
  • The Belmont mast in Lincolnshire, a guyed mast is, after it was shortened in April 2010, 351.5 metres (1,153 ft) high, making it the 2nd highest structure of any kind in the UK after Skelton.
  • Torreta de Guardamar, a VLF-transmission mast of Spanish military near Guardamar is 370 metres tall
  • Gerbrandy Tower in Lopik is 366.9 metres tall.
  • The Eiffel Tower is 300 metres (984 ft) high, with an additional 24 metres (79 ft) antenna on top.
  • The Riga radio and TV tower is the tallest freestanding structure in the EU, at 368.5 m (1209 ft)
  • The Ostankino Tower, in Moscow, is the tallest freestanding structure in Europe, at 540 metres (1772 ft).

Media

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Building Activity

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