The BBC warns viewers that TV reception may be affected by atmospheric conditions during the Christmas period.
- Picture break-ups and audio glitches symptom of weather-related interference.
- Radio services may also suffer issues.
Atmospheric conditions around the northern edge of an area of high pressure passing to the south of the UK over Christmas could cause problems for TV viewers and radio listeners tuning into their favourite programmes over the holidays.
The BBC is warning TV viewers and radio listeners they may “experience periods of interference affecting reception of television and radio services”.
Picture break-up and audio glitching may be a symptom of atmospheric interference.
The interference is caused by a phenomena called tropospheric ducting, associated with strong areas of high pressure. It can cause TV signals from distant transmitters to interfere with local services. As TV services are broadcast across different frequencies, it’s possible that only some services suffer from break-up and pixilation, while reception of other channels remains good. Radio is also liable to disruption, with DAB listeners subject to a bubbling sound or full dropout of audio.
As the week progresses, southern Britain is more prone to the issues, before high pressure moves away.
Who is affected?
Affected TV platforms include:
- Digital Terrestrial Television (Freeview)
- Digital Audio Broadcasting (DAB Digital Radio)
- Analogue FM radio
In addition, users of TV platforms that piggyback off Freeview, including YouView and Freely (where a TV aerial is plugged in) may also be affected.
Reception problems may be worse both at breakfast time and in the evening, when interference is most likely to be noticed.
Who isn’t affected by the TV reception warning…
Satellite and cable reception is not affected. Streaming services aren’t normally affected, either, although those reliant on mobile data services could see fluctuations in their mobile signal, plus higher latency and ping times.
What to do if you lose reception
Viewers are advised not to retune their device.
Normal reception will resume as soon as atmospheric conditions normalise. However, if poor reception continues after the weather has changed, you may wish to consult an aerial installer.
In the meantime, you can stream programmes via the internet, using apps like the BBC iPlayer, ITVX and My5.
Why is this a problem?
Terrestrial TV and radio and the laws of physics…
Normally, Digital Terrestrial Television (Freeview), DAB and FM radio signals only reach as far as the horizon as seen from the transmitter mast, which are generally located on a hill or a tall structure (or better still a tall structure on top of a hill). This creates a defined normal coverage area.
During certain weather conditions, tropopheric ducting can bend radiowaves over the horizon to reach far beyond their normal coverage area.
Terrestrial TV and radio services are planned and co-ordinated across national boundaries to reduce interference.
However, as the number of frequencies allocated to TV services has shrunk in the last decade following digital switchover (DSO) to accommodate 4G and 5G mobile services, it’s more likely that TV services will be subject to interference during certain weather conditions. This is especially so in areas subject to incoming interference from the near continent. The risk of increased interference led to additional relay transmitters being installed, such as in Ashford (Kent) and in Essex.
By: Marc Thornham | Updated: 24/12/2024 14:45