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London to bid farewell to analogue TV

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Crystal Palace TV transmitter Interior

© Digital Spy / Andrew Laughlin

Tomorrow marks a significant milestone in the UK's television history as the key Crystal Palace transmitter group serving London begins the end of the analogue era.

This is a major step towards completion of a project that has dealt with fire, endangered wildlife and disgruntled neighbours to take Britain into the digital age.

At midnight on April 4, the 219-metre high Crystal Place transmitter - serving 4,858,000 households in the capital and the surrounding counties - will officially start the switchover process.

Analogue BBC Two will be the first to disappear forever, followed by the remaining analogue public service channels on April 18, with digital terrestrial television (DTT) - or Freeview signals - boosted in their place. Among Crystal Palace's 52 relay stations, 49 will get Freeview for the first time following the switch.

Arqiva Crystal Palace
To mark the completion of the switchover on April 18, transmission firm Arqiva intends to illuminate the tower with 200,000 watts of lighting, equivalent to 7.5bn candles, sending brightly coloured beams firing out across the capital.

Constructed in the 1950s on the old site of the Crystal Palace building at Sydenham Hill, the station carries all six DTT multiplexes, or 'muxes' - on which multiple channels are delivered over the same frequencies.

Peter Heslop, the digital switchover (DSO) director at Arqiva, said that the process is all about "increasing choice" for consumers, bringing hundreds of TV and radio channels instead of just five analogue networks, but also safeguarding the UK for the next wave of TV evolution.

With a budget of £630m, the digital switchover is the largest capital programme in UK TV history, and the fruits of eight years labour for the BBC and Arqiva.

But it is easy to underestimate the significance of the switchover, particularly due to the fact that more than 93% of the UK already takes a digital TV service from either Freeview, cable, satellite or IPTV, according to figures from Ofcom.

There is still thought to be more than 1m TV sets still connected to analogue TV signals in the UK, although many of those are most likely 'second sets', used in a room other than the main living room where analogue is still available.

As of last month, 940 stations have switched to digital, covering 11 out of the 15 UK regions and 63% of the population. Due to its size, Crystal Palace will add a further 18% of coverage pretty much overnight. By the end of the switchover in October, 98.5% of the British population will be able to access Freeview.

Freeview logo
The first transmitter switched back in 2009, and should everything go to plan up to the Northern Ireland switch on October 24, thus ending the analogue TV era, the DSO will have been 100% on time across the board - something pretty much unheard of in major engineering projects.

This is also in spite of the complexity of the DSO. Due to the nature of the UK's TV infrastructure, it was not possible to take the route of the US and other countries involving a single-night switchover right across the nation.

Instead, different UK regions had to switch in phases - from the small Scottish islands to the monster Granada TV region serving more than 7.2 million viewers.

Along the way, Arqiva has faced various challenges as it worked to either upgrade, repair or completely rebuild transmitter stations and their relays to beam hundreds of digital networks.

Pace Philips Freeview HD
Consumers may have only needed to retune their set-top boxes following the switch, but for Arqiva going digital meant a mammoth task - not least because all sites were 'live', delivering TV pictures that could not be interrupted during the work.

Another challenge facing the company was the weather, as dealing with towers such as the 900 feet high mast at Selkirk meant perilous work.

Helicopter cranes were used to fit new main and reserve digital antennas, but anything over a 20mph ground wind speed meant the choppers were unsafe to use.

There were also planning headaches closer to the ground, including a challenge from local residents near the Belmont structure, at that stage credited as 'the tallest TV transmitter in England'.

Arqiva logo
After Arqiva submitted plans to reduce the size of the transmitter, the residents applied to get protected status, presumably concerned about losing the 'cache' of living near the tallest TV mast. Arqiva ultimately managed to fend this off, said Heslop with a smile.

Wildlife has posed other issues, including the detection of grasshopper warblers nesting at one site causing construction to be postponed, and similar situations with discoveries of the wood calamint plants and the Irish hare.

In the case of the Merlin bird, the nesting sites were so closely protected that Arqiva was never told where they were, just that they were close, for fear of tipping off egg poachers.

But one of the most high profile incidents came when a fire hit the Beckley transmitter near Oxford in 2010 after a new antenna system set ablaze as it first powered up. Uncomfortably for Arqiva, the transmitter happened to be serving the area that was home to prime minister David Cameron and communications minister Ed Vaizey.

Despite the project having, in Heslop's words, the "unique opportunity to kill people", there has only been one serious health and safety incident to date.

iPhone and Android Freeview App
Alongside standard definition television, the switchover also ushered in high definition in 2009 with the world-first adoption of the DVB-T2 technical standard, enabling Freeview HD.

This summer, the UK's digital terrestrial platform will take the next step in its evolution with the introduction of YouView, the BBC and Arqiva-backed project producing set-top boxes offering video on-demand and internet services as well as the Freeview channels.

As well as bringing benefits to television viewers, the switchover will also boost mobile users as Ofcom intends to auction off the released 800Mhz spectrum to enable operators such as Vodafone and O2 to launch 4G services in the UK.

Crystal Palace TV transmitter Interior
Walking around the Crystal Palace transmitter station and seeing the infrastructure that delivers TV to millions of Londoners, there is a pleasing industrial feel to everything. There are computers, gadgets and gizmos, but they sit alongside cooling systems with taps, pipes that send TV signals buzzing up to the mast and racks of spark plugs.

The rooms containing analogue kit understandably feel more ragged and aged than their clean new digital counterparts. They are filled out with shiny Thomson rigs, glistening combiners and slick flat panel TV monitors, rather than the battered cathode ray tube sets perched on chairs in the old set-up.

But in this digital age where everything is chips, bits and bytes, its easy to forget that there is proper engineering and infrastructure still being built to serve current and future generations.

Among Crystal Palace's network of 52 relay stations is Alexandra Palace, the historic building that was the site of the UK's first 'high definition' television broadcast by the BBC in 1936 - a feat marked by a blue plaque on the wall of the 139-year-old building.

"Maybe one day there will be a blue plaque on this building," pondered Heslop, gazing up at the towering Crystal Palace mast, "marking what has been done here."

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