Ive got a freeview receiver, but my picture occasionally freezes or breaks up?
There is no such thing as perfect reception as far as digital TV goes. The better your aerial installation, the less frequent the picture problems will be. What’s acceptable is subjective. I would suggest one “minor incident” in 20 hours viewing is about as good as it gets. Your problem may not be the aerial. The whole system needs to be in good order, i.e. the aerial, downlead, connectors, splitters, amplifiers etc. You may even have problems with too high a signal level.
