Emley Moor transmitting station

Infobox UK Transmitter
name = Emley Moor


Clear skies over Emley Moor Tower
height = convert|330.4|m|ft|0
gridref=SE222128
built = 1969 - 1971
demolished =
collapsed =
BBC = BBC Yorkshire
ITV = ITV YorkshireLocation map|West Yorkshire
label =
lat = 53.611944
long = -1.664444
caption = Map showing the location of Emley Moor within West Yorkshire.
float = right
background= white
width = 175

Emley Moor is an area of moorland in the village of Emley, in Huddersfield, West Yorkshire, England (national grid reference: SE222128), and also the name of a supertall telecommunications & broadcasting station on the site.

History

The current tower is the third structure to have occupied the site. The original convert|135|m|ft|0 lattice tower was erected in 1956 to provide Independent Television broadcasts to the Yorkshire area. It was replaced in 1964 by a taller convert|385.5|m|ft|0 guyed mast (identical to the structure still standing at Belmont in Lincolnshire).

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 convert|2.75|m|ft|0 diameter tube, convert|275|m|ft|0 long. This was surmounted by a lattice section 107 metres tall and a capping cylinder, bringing the total height to convert|386|m|ft|0. 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
* 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 completely disabled the BBC2 UHF transmitter & 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 (1925 - 2008) 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 was only capable of holding one set of antennas, so many viewers in outlying areas still could not receive colour programmes. The taller mast was brought into service on April 16. 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 & Winter Hill, including the hanging of fifty tons of steel chains within each structure. None of the modified masts has 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.

The structure

The structure is a tapered, reinforced concrete tower. It is the tallest freestanding structure in the United Kingdom at a height of 330.4 metres (1,084 ft). 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 third-tallest freestanding structure in Europe, after the Ostankino Tower at convert|540|m|ft|0 and the Fernsehturm Berlin (current height convert|368|m|ft|0).

The UK Government declared Emley Tower a Grade II Listed Building of 'significant architectural or historic interest' in 2002.

Ownership

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

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" & "Real Radio") over an area of approximately 10,000 km². It is the main station for some 57 relays and repeaters throughout Yorkshire & surrounding counties.In July 2007 it was confirmed by Ofcom that Emley Moor would be remaining a B group transmitter after DSO (Digital Switchover).

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. [http://news.bbc.co.uk/1/hi/england/west_yorkshire/5214240.stm]

Other Structures of Comparable height

* Emley Moor is convert|95|m|ft|0 taller than One Canada Square (Canary Wharf), Britain's tallest building, which is convert|235|m|ft|0 high.
* The Belmont mast in Lincolnshire, which is a guyed mast is convert|387.75|m|ft|0 high, making it the tallest structure of any kind in the UK & EU.
* 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 convert|300|m|ft|0 high, with an additional convert|24|m|ft|0 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).

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.

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 ten miles (16 km) radius and are SW and WNW respectively.
* The tower can be seen from elevated sections of the M1 motorway (on a clear day from almost as far north as J46 Leeds, from almost as far south as J32 M18 and between the M1 and J1 of the M18 itself).
* Poet Simon Armitage wrote a poem about Emley Moor, to accompany a short programme about the tower on BBC2 in the 1990s.
* A section of the collapsed tower was converted for use as a racing control tower at nearby [http://huddersfieldsailing.org.uk/ Huddersfield Sailing Club] .
* In 1997, the top convert|8|ft|m|abbr=on section of the mast was plated in gold leaf and exhibited at the London "British Calamities" exhibition. The mast section has now been split into 16 smaller sections which are awarded each year at the Arqiva Christmas party for calamities within the workplace.
* The top of the current tower is at the same elevation above sea-level as the canteen at the nearby Holme Moss mast.

Channels listed by Frequency

Analogue Radio (FM VHF)

* 105.1 MHz — Galaxy
* 106.2 MHz — Real

=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

* UHF 37 (599.25 MHz) — Five
* UHF 41 (631.25 MHz) — Channel 4
* UHF 44 (655.25 MHz) — BBC One
* UHF 47 (679.25 MHz) — ITV1
* UHF 51 (711.25 MHz) — BBC Two

Digital Television

* UHF 40 (626 MHz) — [http://www.digitalspy.co.uk/terrestrial/mux/ Multiplex] 2 Digital 3&4
* UHF 43 (650 MHz) — [http://www.digitalspy.co.uk/terrestrial/mux/ Multiplex] A SDN
* UHF 46 (674 MHz) — [http://www.digitalspy.co.uk/terrestrial/mux/ Multiplex] B BBC
* UHF 49 (698 MHz) — [http://www.digitalspy.co.uk/terrestrial/mux/ Multiplex] D National Grid Wireless
* UHF 50 (706 MHz) — [http://www.digitalspy.co.uk/terrestrial/mux/ Multiplex] C National Grid Wireless
* UHF 52 (722 MHz) — [http://www.digitalspy.co.uk/terrestrial/mux/ Multiplex] 1 BBC

ee 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
* List of tallest freestanding structures in the world
* The Shard of Glass (London)

References

*

External links

* [http://tx.mb21.co.uk/emley/index.php mb21 - The Transmission Gallery]
* [http://www.aerialsandtv.com/emleymoortx.html Emley Moor TV Transmitter, including co-receivable transmitters]
* [http://www.the-moores.co.uk/MediaGallery/Default.aspx?directory=73 Emley Moor photo gallery at The-Moores.co.uk]
*.
* [http://skyscraperpage.com/diagrams/?b5736 Diagrams - SkyscraperPage.com]
* [http://maps.google.co.uk/maps?f=q&hl=en&geocode=&q=Emley&sll=54.162434,-3.647461&sspn=9.913991,26.586914&ie=UTF8&ll=53.612686,-1.664257&spn=0.00245,0.006491&t=k&z=17&om=1 Google Maps]
* [http://maps.live.com/default.aspx?v=2&cp=53.612785~-1.66423&style=a&lvl=17&tilt=-90&dir=0&alt=-1000&encType=1 Live Maps]