page_title: Digital terrestrial television in the United Kingdom
section_title: The switchover process
hierarchical_section_title: Digital terrestrial television in the United Kingdom / Digital switchover / The switchover process
caption_attribution_description: Digital Switchover advertisement in Portmadog, Wales. When this photo was taken, the start of digital switchover was about a month away (stage 1, when BBC 2 analogue disappears, would be on 21 October 2009)
context_page_description: Digital terrestrial television in the United Kingdom encompasses over 100 television, radio and interactive services broadcast via the United Kingdom's terrestrial television network and receivable with a standard television set. The majority of digital terrestrial television services, including the five former analogue channels, are broadcast free-to-air, and a further selection of encrypted pay TV services are also available.
  Freeview is the only DTT service since Top Up TV closed in 2013. BT TV services are carried via IPTV signals.
  The digital broadcasting technology adopted in the UK is the DVB-T system carrying compressed digital audio, video and other data in a combined transport stream, using COFDM modulation. A total of eight national and one local 'multiplexes' are broadcast in the UK, guaranteed to reach over 90% of the country. Three of the multiplexes, carrying the free public service channels operated by the BBC, ITV, Channel 4, S4C and Channel 5, are guaranteed wider coverage still, reaching 98.5% of the country including areas dependent on low-power local relays.
context_section_description: After several months of press publicity, leaflet drops, public meetings etc., captions started appearing on analogue broadcasts from the affected transmitters, warning viewers that the analogue service would shortly be switched off and that they would need to take action (for Whitehaven, the first large area to switch over, the captions started appearing some 5 months before the BBC Two analogue service was switched off). At about the same time, details of the Switchover Help Scheme were distributed. Although viewers who lived outside existing Freeview reception areas were unable to test any digital receiving equipment they had bought at this early stage, test-screens on Ceefax (BBC One & Two) and Teletext (ITV & C4/S4C) page 284 made it possible to determine whether they were likely to need a new aerial or a signal amplifier to receive digital transmissions.
  Next, detailed information booklets were delivered to all households in the area (including many on the fringe who may have been receiving their TV from other transmitters- hence the importance of the on-screen warning captions). Two or three months later, the first stage of the switchover began with the analogue BBC Two replaced with the new BBC A multiplex. At some locations, during the period between stage one and stage two, BBC One, ITV or Channel 4 moved to the analogue BBC Two frequency where that channel's frequency was required for the digital transmission of Multiplex 1. At the same time, captions appeared on the remaining analogue channels reminding viewers of the impending switchover. Finally, the second stage saw the remaining analogue transmissions switched off and the other high power multiplexes switched on. Initially, this occurred four weeks after stage one, but starting with the switchover at Mendip in April 2010 onwards, this gap was reduced to two weeks.
  Three multiplexes (BBC A, D3&4, BBC B) are for public service broadcasting and are broadcast from all transmitter sites. They contain around 25 TV channels, half a dozen radio stations and half a dozen text/interactive services. These include all the television channels from the BBC, some from ITV and Channel 4, Channel 5 and S4C (in Wales only). The other three multiplexes (SDN, Arqiva A, Arqiva B) are broadcast from main transmitter sites only and are operated by their respective commercial licence-holders. To reflect the slightly changed roles, the multiplex names were also changed:
caption: Digital Switchover banner in Porthmadog, Wales, as seen in September 2009
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