Supplementary memorandum from Digital
UK
Further to evidence given to the CMS Select
Committee on 8 November 2005, in which it was suggested that the
staggered channel switchover will not be possible in all regions,
Digital UK has drafted this note to explain the staggered process
and confirm that this process will be adopted in all regions.
THE STAGGERED
CHANNEL SWITCHOVER
IN BERLIN
A key learning from the Berlin switchover was
the benefits brought by a staggered channel switchover, in which
one channel would switch to digital first, followed by an intervening
period before the remaining channels switch.
In Berlin one analogue channel was switched
to digital in November 2002. This allowed households to understand
whether they would receive DTT and purchase new receivers. Four
months later, in February 2003, all national commercial broadcasts
switched to digital. In a third stage, in August 2003 the remaining
low-power analogue public service broadcasts switched to digital,
and all analogue transmission was switched off.
HOW STAGGERED
CHANNEL SWITCHOVER
WILL WORK
IN THE
UK
A similar method is being used in the UK. The
following diagram is an illustration of the switchover process
at the Blackhill transmitter in North Lanarkshire, Scotland:
The process described by this diagram is:
1. Around 18 months to two years before
the switchover date the antenna at the top of masts are re-engineered
for digital but used for analogue transmissions until the switchover
date.
2. Approximately three months before switchover
engineering works on the ground commence.
3. BBC2 displays a caption telling the viewer
that it will shortly be switched over to digital.
4. BBC2 switches to digital, and one of
the BBC PSB multiplexes (carrying BBC2 in digital form plus five
to eight other digital channels) is launched in its place. At
this time a viewer previously outside DTT coverage will be able
to access the services carried on that multiplex. Those within
existing DTT coverage will be required to re-scan their boxes
(many do this automatically) to pick up the bundle of channels
carried on this multiplex.
5. Captions appear on the remaining terrestrial
analogue channels (BBC1, ITV, Channel 4 and Five).
6. After an interval of a few weeks, the
remaining analogue channels switch to digital. The other two PSB
multiplexes (the second BBC multiplex and the Digital 3&4
multiplex operated by ITV and Channel 4) are launched in their
place. Five is carried on one of the BBC multiplexes. All PSB
services are now available in digital form. Again, those within
existing DTT coverage must perform a re-scan to find the other
PSB multiplexes in their new locations.
7. Depending on the circumstances at each
transmitter site the commercial multiplexes (the SDN multiplex
and the two National Grid Wireless—previously Crown Castle—multiplexes)
will either move to their new channel frequencies at the same
time as the PSB multiplexes or a few weeks later.
Digital UK has been working with the broadcasters
and transmission companies (Arqiva and National Grid Wireless—who
between them own the whole transmission network of 1,154 sites)
to develop this plan. It is supported by them, and is seen as
the best possible way of giving viewers an opportunity to test
their DTT signal and prepare for the switchover of the remaining
channels.
This process will be adopted at all sites across
the UK at switchover.
15 November 2005
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