Crystal Palace transmitting station

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Template:EngvarB Template:Use dmy dates Template:Infobox UK transmitter The Crystal Palace transmitting station is a broadcasting and telecommunications site in the London Borough of Bromley, England (Template:Gbmapping).

Its tower is the fifth-tallest structure in London. It is best known as the main television transmitter for the London area, and is owned and operated by Arqiva.

History and development

The station was constructed in the mid-1950s among the ruins of the Crystal Palace. The Aquarium on whose site it stands was destroyed in 1941 during the demolition of the Palace's north water tower.<ref name="time-north-tower">Template:Cite journal</ref><ref name="pescod-north-tower">Template:Cite journal</ref> (John Logie Baird's earlier transmitter and TV studios were a separate development at the other end of the Palace and perished with it in 1936.<ref name="transdiffusion-baird">Template:Cite web</ref><ref name="soundscapes-baird">Template:Cite journal</ref>) Its new Template:Convert<ref name="bromley-council" /> tower was the tallest structure in London until the construction of One Canada Square at Canary Wharf in 1991.

The first transmission from Crystal Palace took place on 28 March 1956, when it succeeded the transmitter at Alexandra Palace where the BBC had started the world's first scheduled television service in November 1936. In November 1956 the first colour test transmissions began from Crystal Palace relaying live pictures from the studios at Alexandra Palace after BBC TV had closed down for the night. In May 1958 the first experimental Band V 625-line transmissions started from Crystal Palace.

This tower was designed and built for BBC by British Insulated Callender's Construction Co Ltd with steelwork fabrication by Painter Bros Ltd, Hereford. The tower was required to transmit television programmes with good reception in 1957 and has a total height of Template:Convert. The base of the tower is Template:Convert to a side and it rises in twelve diminishing panels to a Template:Convert square platform at a height of Template:Convert.<ref name="bbc-monograph-23">Template:Cite journal</ref> The tower was constructed using two masts as derricks, one Template:Convert and the other Template:Convert high in conjunction with a winch. A 16mm film was produced of the construction by BICC at the time which was available on loan from the BICC Film Library.

When built it transmitted BBC Television on the VHF 405-line system; the Croydon transmitter two miles away had been built some months earlier to broadcast ITV. When UHF transmissions started in 1964, first the new BBC2 and later both ITV and BBC1 were transmitted from Crystal Palace. 405-line VHF television was discontinued in 1985, and all television broadcasts from Crystal Palace were on UHF. On 18 July 1986, with the First Night of the Proms on BBC2, the transmitter became the first in the world to transmit stereophonic sound using the NICAM digital sound system. Crystal Palace did not transmit analogue Channel 5: this (alone) came from Croydon. Croydon had reserve transmitters for ITV and Channel 4, used in the event of a fault or maintenance at Crystal Palace. The BBC decided that a complete reserve was also a good idea and all four services became available from Croydon if required.

The station carried the London regions of BBC One, BBC Two, ITV1 and Channel 4 in analogue, each with an effective radiated power of 1 MW, before the digital switchover took place during April 2012, as well as all six digital terrestrial television multiplexes. These had an ERP of 20 kW before switchover and 200 kW after, with considerable beam tilt to the south and east. With digital switchover completed all services come from Crystal Palace again, but because of the site's importance Croydon will be able to duplicate the PSB multiplexes in case of emergency. 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.

It is also used for FM radio transmission of local radio stations BBC London 94.9, XFM, Capital Xtra and Absolute Radio, and a low-powered relay of the four BBC national FM services and Classic FM. It also has medium wave transmitters on 558 kHz (Spectrum Radio), 720 kHz (BBC Radio 4) and 1035 kHz (Kismat Radio). Since the tower is grounded, a wire aerial spun close to it is used for the MW services.

Since 1995, the tower has been 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 since started transmitting.

In May 2006 it began broadcasting the first terrestrial HDTV signals in the UK to a trial group of 450 London homes to test HD broadcasts by the BBC, ITV, Channel 4 and Five, to assess the viability and potential problems of future nationwide HD broadcasting. On 2 December 2009, the site entered service as one of the first DVB-T2 transmitters in the world, carrying a variant of the BBC's Multiplex B broadcasting high-definition TV services.

Digital switchover

The Government's plans for digital switchover were based on the use of almost all current analogue TV transmitter sites. Crystal Palace remains a key part of the network since analogue was switched off in the London area in April 2012. In July 2007 it was confirmed by Ofcom that Crystal Palace would remain an A group transmitter after DSO (digital switchover).

On 18 April 2012 a public lighting display was performed from the tower to mark the last day of analogue TV broadcasts from the transmitter.<ref name=DMSwitchover>Template:Cite news</ref><ref name=ArqivaSwitchOver>Template:Cite web</ref>

Channels listed by frequency

Analogue radio (AM medium wave)

Frequency kW Service
558 kHz 1 Spectrum
720 kHz 0.75 BBC Radio 4
1035 kHz 2.5 Kismat Radio

These frequencies were used by Lots Road until Tuesday 25 September 2007.

Analogue radio (FM VHF)

Frequency kW Service
88.8 MHz 4† BBC Radio 2
91.0 MHz 4† BBC Radio 3
93.2 MHz 4† BBC Radio 4
94.9 MHz 4 BBC London 94.9
96.9 MHz 0.03 Capital Xtra
98.5 MHz 4† BBC Radio 1
100.6 MHz 2 (V)† Classic FM
104.9 MHz 2.9 XFM
105.8 MHz 3.73 Absolute Radio

† Relay of Wrotham.

Digital radio (DAB)

Frequency Block kW Operator
222.064 MHz 11D 6.5 Digital One
223.936 MHz 12A 2.1 Switch London
225.648 MHz 12B 10 BBC National DAB

Template:Col-start Template:Col-2

Digital television

Frequency UHF kW Operator System
Template:UK DVB-T 22 200 Arqiva A DVB-T
Template:UK DVB-T 23 200 BBC A DVB-T
Template:UK DVB-T 25 200 SDN DVB-T
Template:UK DVB-T 26 200 Digital 3&4 DVB-T
Template:UK DVB-T 28- 200 Arqiva B DVB-T
Template:UK DVB-T 30- 200 BBC B DVB-T2
Template:UK DVB-T 33 36.3 Arqiva C DVB-T2

Template:Col-2

Before switchover

Template:No2Frequency Template:No2UHF Template:No2kW Template:No2Operator Template:No2System
Template:UK DVB-T 22- 20 Digital 3&4 (Mux 2) DVB-T
Template:UK DVB-T 25- 20 BBC (Mux 1) DVB-T
Template:UK DVB-T 28- 20 BBC (Mux B) DVB-T
Template:UK DVB-T 29- 20 Arqiva (Mux D) DVB-T
Template:UK DVB-T 31 10 BBC B (Mux HD) DVB-T2
Template:UK DVB-T 32- 20 SDN (Mux A) DVB-T
Template:UK DVB-T 34+ 20 Arqiva (Mux C) DVB-T

Template:Col-end

Analogue television

BBC Two analogue was shut down on UHF 33 on 4 April 2012 and ITV1 was moved from UHF 23 into its frequency temporarily. The other analogue services shut down on 18 April 2012.

Template:No2Frequency Template:No2UHF Template:No2kW Template:No2Service
Template:UK System I 23 1000 ITV1
Template:UK System I 26 1000 BBC One
Template:UK System I 30 1000 Channel 4
Template:UK System I 33 1000 BBC Two

See also

Template:Portal

  • Arqiva (which owns the tower)
  • List of radio stations in the United Kingdom
  • List of tallest buildings and structures in Great Britain
  • List of tallest towers in the world
  • Radio masts and towers
  • Tall buildings in London

References

Template:Reflist

Bibliography

  • R. W. Burns, British Television: The Formative Years, IET (1986), ISBN 0-86341-079-0
  • R. H. Evans, The Crystal Palace FM filler experiment, British Broadcasting Corporation, Division of Engineering, Research and Development Department (1996), ASIN B0018RJ1ZY

External links

Template:Commons category

Template:Television transmitters in the UK Template:Crystal Palace VHF 405-line Transmitter Group Template:Supertall Template:London landmarks Template:Coord