I was looking on the 'Freeview' website yesterday because I'd heard on the grapevine that a 'retune' would be required v.soon (actually this afternoon/evening) and I also saw that a while back there was problems with the signal from several BBC channels, so this backs up your comments. They didn't say what the cause was though, but it was long ago enough that it should've been fixed by now.

A few things to note about freeview digital signals compared to the old defunct analogue ones:

Digital freeview channels are transmitted on far lower power than the analogue ones were (often 10x less), and as they are also using compressed data, they are vulnerable to changeable weather (especially high pressure or windy weather), and the signal can suddenly drop off the proverbial cliff from looking great to pixelated rubbish or nothin at all.

I find in periods of that sort of weather, you have to carefully choose which channels you leave the PVR on whilst it records another - mine seems to work better if you leave it on the same channel as you're recording, second best is one from the same group (mux), and lastly from a different group. Same goes when recording two channels at once - many PVRs will allow the viewer to watch a third live if two of those channels are in the same group (it doesn't matter which), but there's a greater chance in the singal dropping out/pixelating in those weather conditions.

You may also find that at certain times of the day, may due to atmospherics, wind direction or something else (who knows what?) the signal drops off enough for the cliff edge quality problem to happen. It could very well be that the OP's signal stength is poor anyway, but for the reasons I stated above they don't notice it, as signal 'quality' is not the same as signal strength, and often are unrelated. They may even find that due to a nearby growing tall tree, the signal is affected at certain times of the day (this happened at my parents' home and eventually the owners of the trees pruned them, resulting in a better signal!

I'm also wondering whether the retune last month so that we could view all the extra BBC 'red button' channels (Wimbledon tennis coverage) may have contributed to the problem. The signal to my PVR (I don't have a freeview TV, so I can't compare - it acts as a monitor only) has been naff of late, so I'll see what happens after today's retune when (presumably) most of the extra red button channels disappear again.

Some of the new 4G phone services use TV spectrum freed up by move to digital. Interference with digital TV is a known problem due to technical issues but can be solved with filters etc that 'notch out' the unwanted signal.

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