Tv

[GreatWall]

is anyone having problems with their HD versions of a channel - my normal version if ok but HD versions are sticking

[davebro]

I don't tend to use HD (not got HD eyesight!).

What are you using? Freeview/Freesat/Sky/Cable?

[aelmpvw]

i don't bother with hd, i can't see the difference

[bhg481]

HD broadcasts are on a different channel to the normal broadcasts. It could be that your aerial, which compromises on element sizes, is better suited for non-HD channels. It might only become obvious if there is a signal problem such as weather or transmitter maintenance.

[Buenchico]

As Bhg481 says, HD channels use different multiplexes to SD ones. (A 'multiplex' is a bundle of channels, which all share a common frequency).

In an ideal world, you should have a different TV aerial for each multiplex, so that each aerial would have elements of exactly to the right length to 'resonate' perfectly with the frequency of the incoming signal. However that would mean that we'd need seven TV aerials on the roof of every house, in order to receive all of the national channels (because their signals are distributed across seven different multiplexes). In practice, therefore, we just use a single aerial which, inevitably, will be better at resonating with some frequencies than with others.

The foregoing situation can be fine when reception conditions are good, with all seven multiplexes being adequately 'pulled in' by a single aerial. However when conditions worsen (through high solar activity, high solar pressure, large amounts of precipitation, etc), the aerial can continue to 'pull in' signals from multiplexes that use frequencies well-suited to the lengths of its elements but it can't provide sufficient signal strength for reliable reception of signals on less well-favoured multiplexes.

Reception conditions are currently poor across much of the UK, due to high atmospheric pressure. So your aerial isn't fully up to the job of receiving signals from HD multiplexes. The problem will almost certainly go away when the atmospheric pressure drops but you might still want to consider boosting the signal from your aerial to your TV by purchasing one of these
https://www.argos.co.uk/product/9383027
together with one of these
https://www.screwfix.com/p/philex-coaxial-cable-1m/41720

A related current thread:
https://www.theanswerbank.co.uk/How-it-Works/Question1781303.html