Predicted coverage of public service and commercial digital television multiplexes following switchover

Ofcom believes that stakeholders may find it useful to have some background on terrestrial digital television coverage. Below is some information on UK-wide and individual transmitter coverage based on the facts currently available to Ofcom ^(-1-)

Background

During the period from 2008 to 2012, analogue television services will be replaced by digital television services across the UK, a process known as digital switchover.

In December 2006, Ofcom made a statement on the coverage that must be achieved by these digital television services post switchover ^(-2-). In this statement Ofcom confirmed that it would include conditions in the licences of the Public Service Broadcasters (PSBs) to ensure that their terrestrial digital services substantially match the coverage achieved by analogue television services. There are similar conditions on the BBC’s services not licensed by Ofcom through its Charter and Agreement.

In the same statement, Ofcom also confirmed that the post-switchover coverage of the three commercial multiplexes should at least match that which they currently achieve.

To achieve these coverage objectives, the PSBs will broadcast their three digital multiplexes from all existing analogue transmitter sites. The three commercial multiplexes will broadcast from a smaller number of transmitters, but at least from the transmitters that they currently use.

UK Frequency plan

Digital broadcasting frequency plans were agreed across Europe at an international planning conference held in Geneva in 2006. This agreement forms the backbone of the UK’s digital switchover plan and the coverage figures presented below are based upon the latest version of the UK’s frequency plan ^(-3-). However, some work is still being carried out to optimise the plan, and discussions are continuing with our neighbours in Europe to maximise coverage. Some small changes may therefore occur.

The latest plan assumes that the PSB multiplexes will be broadcast from 1,160 transmitter sites and the commercial multiplexes from 80 transmitter sites ^(-4-).

Comparison of UK-wide coverage figures

Below are two tables illustrating the current and future coverage for terrestrial television services. For consistency, both sets of figures have been derived using the same frequency planning model.

Table 1 provides UK-wide figures for the coverage that is currently achieved by analogue and digital services. In both cases the figures represent core coverage. In the case of analogue television, core coverage taken to be households that are estimated to be able to receive the four analogue services of BBC ONE, BBC TWO, ITV and Channel4/S4C ^(-5-). The 6MUX figure is the number of households estimated to be able to receive all six digital multiplexes.

In Table 2, figures are given for the coverage predicted to be achieved by digital services post switchover. 3PSB coverage refers to households which are predicted to be covered by all three PSB multiplexes, while 6MUX refers to the number of households that are predicted to be able to receive all three PSB multiplexes and the three commercial multiplexes.

Detailed population coverage by transmitter

It is currently assumed that the commercial multiplexes will broadcast from 80 transmitter sites. Figures have been presented in Table 3 for the gross coverage expected to be achieved by the PSB and commercial multiplexes from these 80 transmitters.

Gross coverage refers to the maximum area that a transmitter can cover. All households that are predicted to be able to receive a service from the transmitter in question are counted, even if they are in areas which have an overlapping service from neighbouring transmitters. Thus, households in areas where transmitters overlap are counted several times over, once for each transmitter that can be received. The actual number of households that receive services from a particular transmitter (generally referred to as net coverage) will in general be somewhat lower.

Ofcom
8 February 2007

Footnotes:

1.- While every reasonable effort is made to ensure that the information provided in this document is accurate, no guarantees for the currency or accuracy of information are or can be made. The information contained in this document is provided without any representation or endorsement made and without warranty of any kind, whether express or implied.

2.- The Statement on switchover related changes to DTT licences is available on the Ofcom website

3.- Version 5.41, November 2006

4.- SDN multiplex additionally operates from the Ferryside transmitter but as the coverage is very low this is not included in these figures

5.- A shortage of available frequencies means that the coverage achieved by Channel 5 (Five) is less extensive than the four longer-established analogue networks.