Crystal Palace transmitting station

Arqiva Crystal Palace
Crystal Palace transmitting station (Greater London)
Tower height 219 metres (719 ft)[1]
Coordinates 51°25′27″N 0°04′30″W / 51.424167°N 0.075°W / 51.424167; -0.075Coordinates: 51°25′27″N 0°04′30″W / 51.424167°N 0.075°W / 51.424167; -0.075
Built 1956
BBC region BBC London
ITV region ITV London
Local TV service London Live

The Crystal Palace transmitting station, currently known as Arqiva Crystal Palace, is a broadcasting and telecommunications site in the Crystal Palace area of the borough of Bromley, England (grid reference TQ339712).[2]

The station is the fifth-tallest structure in London, and is best known as the main television transmitter for the London area. As such, it is the most important transmitter in the UK in terms of population covered. The transmitter is owned and operated by Arqiva.

History and development

At night

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.[3][4] (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.[5][6]) Its new 219-metre (719 ft)[1] 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 Brothers Ltd, Hereford. The tower was required to transmit television programmes with good reception in 1957 and has a total height of 708 feet (216 m). The base of the tower is 120 feet (37 m) to a side and it rises in twelve diminishing panels to a 14.5 feet (4.4 m) square platform at a height of 429 feet (131 m).[7] The tower was constructed using two masts as derricks, one 230 feet (70 m) and the other 125 feet (38 m) 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.[8][9]

Innovations

The transmitter was the first in the UK to broadcast (experimentally) on 625 lines (UHF) in 1964, which it did on Channel 44.

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.

Television

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.

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.

Radio

It is also used for FM radio transmission of local radio stations BBC Radio London, Radio X, 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 span 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.

High definition

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). The transmitter is only one of two (the other being the ITV Granada transmitter at Winter Hill) that now solely provides high power ITV and BBC services for the whole of their region, although still supported by the usual network of relays. Between opening in 1974 and January 1982 the main transmitter at Blue Bell Hill broadcast ITV London signals to much of north and central Kent. However reorganisation of franchises saw Blue Bell Hill transferred to a new dual-region of ITV South and South-East and from 1 January 1982 Blue Bell Hill began broadcasting ITV Television South (better known as TVS). Bluebell Hill now transmits ITV Meridian and BBC South East.

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.[10][11]

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 Lyca Dil Se

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 Radio London
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 Radio X
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

Digital television

Frequency UHF kW Operator System
482.000 MHz 22 200 COM5 (ARQ A) DVB-T
490.000 MHz 23 200 PSB1 (BBC A) DVB-T
506.000 MHz 25 200 COM4 (SDN) DVB-T
514.000 MHz 26 200 PSB2 (D3&4) DVB-T
529.833 MHz 28- 200 COM6 (ARQ B) DVB-T
538.000 MHz 29 20 LTVmux DVB-T
545.833 MHz 30- 200 PSB3 (BBC B) DVB-T2
570.000 MHz 33 43.1 COM7 (ARQ C) DVB-T2
586.000 MHz 35 39.8 COM8 (ARQ D) DVB-T2

Before switchover

Frequency UHF kW Operator System
481.833 MHz 22- 20 Digital 3&4 (Mux 2) DVB-T
505.833 MHz 25- 20 BBC (Mux 1) DVB-T
529.833 MHz 28- 20 BBC (Mux B) DVB-T
537.833 MHz 29- 20 Arqiva (Mux D) DVB-T
554.000 MHz 31 10 BBC B (Mux HD) DVB-T2
561.833 MHz 32- 20 SDN (Mux A) DVB-T
578.166 MHz 34+ 20 Arqiva (Mux C) DVB-T

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.

Frequency UHF kW Service
487.25 MHz 23 1000 ITV (Thames Television/LWT/Carlton Television)
511.25 MHz 26 1000 BBC One
543.25 MHz 30 1000 Channel 4
567.25 MHz 33 1000 BBC Two

See also

References

  1. 1 2 "NGW planning application". Bromley Council planning portal. 23 April 2008. Retrieved 13 September 2008.
  2. ↑ BBC Milestones. Retrieved 13 October 2008
  3. ↑ "War's Worst Raid". TIME. 28 April 1941. Retrieved 29 May 2008.
  4. ↑ Pescod, David FLS (10 February 2005). "Correspondence" (PDF). The Linnean. London: Linnean Society of London. 21 (2): 15. Retrieved 1 August 2012.
  5. ↑ Elen, Richard G (5 April 2003). "Baird's independent television". Transdiffusion Broadcasting System. Retrieved 5 April 2015.
  6. ↑ Herbert, Ray (July 1998). "Crystal Palace Television Studios". Soundscapes. Groningen, The Netherlands: University of Groningen. 1 (4). ISSN 1567-7745. Retrieved 29 May 2008.
  7. ↑ Wharton, W.; Platts, G. C. (February 1959). "The Crystal Palace band I television transmitting aerial" (PDF). BBC Engineering Division Monograph. British Broadcasting Corporation: 5. Retrieved 12 October 2013.
  8. ↑ "The BBC's Crystal Palace Television Tower". Construction Bulletin. British Insulated Callender's Construction Company Ltd (11). December 1957.
  9. ↑ Engineering: 246. 21 February 1958. Missing or empty |title= (help)
  10. ↑ Revoir, Paul (19 April 2013). "Crystal Palace transmitter lights up the night sky as it broadcasts analogue signal for the last time after 56 years.". Daily Mail. Retrieved 15 June 2013.
  11. ↑ "Switch Over Night". Arqiva website. Arqiva. Retrieved 15 June 2013.

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