Crystal Palace Transmitter
From Free net encyclopedia
The Crystal Palace Transmitter is a telecommunications tower in the Crystal Palace area of South London (Template:Gbmapping). Today it is the second-tallest structure in London. It is best-known as the main television transmitter for the London area.
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History and development
Constructed in 1950, at 222 m (728 ft) tall it was the tallest structure in London until the construction of the 1 Canada Square tower at Canary Wharf in 1991. Despite its size, it has been largely overlooked as London landmark due to its location and simplicity. It has been nicknamed London's Eiffel Tower.
The tower is currently used for UHF television broadcasting. It carries the London regions of BBC One, BBC Two, ITV 1 and Channel 4 in analogue, each with an effective radiated power of 1 MW, as well as all six digital terrestrial television multiplexes. These have an ERP of 20 kW, with considerable beam tilt to the south and east. Although DTT requires far less power to achieve the same coverage as analogue TV, this 17 dB difference is too large to ensure comparable coverage. The station therefore has a range of about 30 miles (50 km) for DTT, compared with about 60 miles (90 km) for analogue.
The tower is also used for FM radio transmission of several local radio stations BBC London 94.9, XFM, LBC 97.3, Choice FM and Virgin Radio, as well as a low powered relay of the 4 BBC national FM services and Classic FM. It also has mediumwave transmitters on 558 kHz (Spectrum Radio), 720 kHz (BBC Radio 4) and 1035 kHz (Kismat). Since the tower is grounded, a wire aerial spun close to it is used for the MW services.
Since 1995, the tower has also been in use as one of five London transmitters for the BBC DAB multiplex. This was joined in 1999 by the Digital One DAB service, and a further local DAB multiplex has also since started transmitting.
Future developments
The UK Government's plans for digital switchover are based on the use of almost all of the UK's current analogue TV transmitter sites. As such, Crystal Palace is expected to remain a key part of the network when the London area is switched over in 2012.
Channels listed by frequency
- Analogue Radio (AM Medium Wave)
- 558 kHz - Spectrum
- 720 kHz - BBC Radio 4
- 1035 kHz - Mean Country
- Analogue Radio (FM VHF)
- 88.8 MHz - BBC Radio 2
- 91.0 MHz - BBC Radio 3
- 93.2 MHz - BBC Radio 4
- 94.9 MHz - BBC London
- 96.9 MHz - Choice FM
- 98.5 MHz - BBC Radio 1
- 100.6 MHz - Classic FM
- 104.9 MHz - XFM
- 105.8 MHz - Virgin Radio
- Digital Radio (DAB)
- Block 11D: 222.064 MHz - Digital One
- Block 12A: 223.936 MHz - Switch London
- Block 12B: 225.648 MHz - BBC
- Analogue Television
- Digital Television
- Amateur radio
- GB3SL, the South London 2m FM repeater which had its output at 145.650 MHz, the input is at 145.050 MHz. This was on the tower on one of the lower parts of the tower. It has now been superseded by a VHF repeater (GB3OK) in Orpington which operated on the same frequencies until April 2006 when a channel change was carried out.
Notes
- The five television channel uses the nearby Croydon Transmitter for its London analogue transmission.
- Two further local DAB multiplexes are also transmitted from the Croydon transmitter.
- Wrotham Transmitter is the main radio transmitter serving London for the 4 BBC national FM services and Classic FM.
- Brookmans Park Transmitter and Droitwich AM transmitter provide the BBC national services to London on medium wave and long wave respectively.
External links
- Mike Brown's page
- http://en.structurae.de/structures/data/index.cfm?ID=s0016652
- Ofcom local transmitter advice