- If you are using an 'old' TV and relying on a STB (Set Top Box), and you lose some channels it's not a TV issue.
- If you only have a TV and lose some channels it wont be a TV issue, as the tuner will either work or won't. Do you have a radio that only picks up 891 but not 1395(I think not)?
- If you are only using a STB the above point will be the same, you wont need a new STB
Digital signals work differently to analogue, basically they work or don't ( I appreciate it can pixelate a bit but usually you have a picture or no picture). With analogue system you can turn in and get distortion and bad signals, as I am sure you all remember.
Each TV, STB, PVR etc has different thresholds as when to pick up a signal or not. You may have a TV that will show channels that have a weak signal, whereas other devices will only show when the signal is strong (so it doesn't cut out). I would think the issue Tyke is having (or was happening) is a poor connection, either the cable or the aerial.