Thanks for that as I hadn't spotted it. I am very marginal so it just takes something small to give me problems.
The Downdetector website looks useful apart from the ignorance and arrogance of 90% of the posters. It is rather dispiriting and I fear a sign of our times.
@FreeviewAdvice please explain why you’ve told my elderly parents in rural North East Scotland that they have had absolutely no Freeview signal at all for 3 DAYS due to ‘atmospheric pressure’ and still refuse to send an engineer to help! Disgraceful!
No you idiot. There is no signal so no point in sending anyone out. Where are engineers going to magic a working signal from?
The BBC page says it is a temperature inversuion caused by the high pressure which is the problem.
However, it isn't the high pressure itself which causes interference with TV signals. It's the presence of what is known as an atmospheric temperature inversion. A temperature inversion is when a layer of warm air overlays cooler air at the surface. Temperature usually decreases with height above the earth's surface, but when there is an area of high pressure, the air aloft sinks down towards the earth's surface and it warms up as it does so.
This creates a sharp thermal contrast in the atmosphere which TV and radio waves see as a physical boundary. There are many TV and radio waves travelling through the lower atmosphere and in such atmospheric conditions, these waves can be refracted or bounce off the inversion overhead and this enables them to travel much further than they would otherwise be able to.
In this way, the usually strong Freeview signals can experience significant interference with other, normally distant, signals from other sources.
Will these conditions persist? Inversions tend to break up. The current high pressure over the UK is likely to slowly weaken over the next couple of days.
Inversions may still form overnight for the next couple of nights, particularly in the south of the UK, but they are not expected to be as sharp or close to the ground and so should have less of an effect on Freeview signals.
| Mon 30 Dec 2019 19:07:48
#3 |
