Since yesterday evening my Freeview box no longer seems to pick up a signal for channels such as Channel 5 +1, Drama & some of the shopping channels. Usually a bad signal from the TV aerial is due to thunderstorms and particularly bad weather, but today it's nice and sunny. It can't be my TV (even though its second hand and 10 years old). Perhaps the Southampton and surrounding areas are weak, I just don't know.

However what makes it more confusing is my parents have a bigger TV next door that doesn't seem to lose the signal as much as my little one (which is also downstairs).

How can I check if its a new TV aerial I need without paying a fortune for an engineer to come out and have a look? Is there any website suggestions to check, or does it need replacing altogether?

It could be interference from another transmitter. In certain atmospheric conditions transmissions travel much further than normal so if there is a spurious signal on top of the one for the affected mux it could confuse the box.

I would not retune for now until you know what the problem is.

You don't say what aerial you have? Is it a set top aerial or an outdoor/loft type? Is it the same aerial your parents use or separate to theirs?

If they have a separate aerial and are not getting the same issues as you then see if they will let you plug your box into their aerial for a quick test. If your box gets the missing channels on their aerial then that indicates it's not the box.

If their TV gets the channels you are missing fine and your box is still missing them then you could try re-tuning on their aerial to see if they return.

If however their TV is having issues on the same channels you are then it might be external to you (and them). Some receivers react better to interference than others so they might be having picture break up but not total loss.

If that is the case all you can do is wait until conditions change and the interference goes away. Or if it was a transmitter fault, that get fixed. But don't retune your box if your parent's TV is also suffering.

Well I noticed on their TV with the channels I am having trouble with that they get occasional interference, but not ongoing like mine. My Dad's away working at the moment, so I can't ask him for advice, and my mum knows about technical stuff even less than I do. It could be a number of the things you mentioned. I guess I'll just have to wait patiently for a natural fix.

It's just unusual to not be able to get a signal from 10pm yesterday till now. Surely all channels wouldn't be appearing if it was an issue at my end.

I have a seperate aerial connection in another downstairs room that I watch TV on. We also have a TV aerial on the roof of our house that connects my TV, the living room's TV and my parents bedroom TV.

Also I've just though that as the weather has been reaching 25ºC in my particular area it could be the transmitter hass overheated and is only projecting maximum signal strength to 1 or 2 out of the 3 TV's.

All you have to do is unplug the aerial from the back of their telly and plug it into yours. If the box and telly are portable enough to drag into your parents room. See if your telly gets the channels on their aerial connection or not and take it from there.

The digital TV channels are transmitted in six groups called muxes. Each on a separate UHF radio frequency. So it is quite possible to get interference that only affects one of those UHF frequencies and not the others. Hence why only some channels have problems and the others are perfectly fine.

Similarly at the transmitter site there are six separate transmitters for the six muxes so there could be maintenance going on on one of those requiring it to be turned off or reduced in power for some reason. Or a fault on only the one transmitter. Again that would only affect one of the six groups of channels and not the others.

Channel 5+1 and Drama are on the same mux along with Quest and 5* and shopping channels like QVC. So if you are having issues with those channels then that suggests you are having problems receiving that particular mux and the others are OK.

Any transmitter that overheats in 25 degree weather is either very badly designed or knackered. Besides the transmitter is probably in a nice air conditioned building keeping it cool

And TV transmissions don't work like that. If the power drops then the signal to ALL TV's in it's service area drops. The power a transmitter puts out is not determined by how many tellies it is serving but the geographical area it is meant to cover.

OP, if you check this UK Free TV page when you have reception problems it will tell you about any planned engineering works or unexpected transmitter faults on the Rowridge (Isle of Wight) mast, which I think will be the transmitter your aerial would pointing to in Southampton.

You can also see the muxes that chrisjr referred to and the TV stations that each mux contains. If you like you can enter your postcode for predicted future changes to Freeview channels.

http://www.ukfree.tv/txdetail.php?a=SZ447865