I think your problem is caused by a tree in your signal path. See the post I just created on this subject.
As Peter said, more than likely a problem with your signal strength, whether there is something in the line of site, or theres a problem with the aerial, might be polarised horizontal instead of vertical. nothing wrong with the signal
Sorry guys the signal was definitely dropped for that day or more at Mt Campbell. I had this problem once before and it was confirmed by the service provider that the Mt Campbell Link was down. Fine ever since, have not touch the aerial or tuning of my freeview box. It was just on the day I posted, nothing since. And all the tree's outside my place are still standing, p.s. I'm at 200m above sea level and not a lot in my way between me and the transmitter.