Yeah, tell me about it...
...the other night, we were watching a channel, and an OTA show was to start recording soon - I think it was Survivor. We checked the channel, and it was clear as a bell - even watched the show start. Went away to watch something else, then went back to the survivor channel (the show was off) and started watching CSI. CSI was perfect. Decided to watch the recorded Survivor while CSI continued to record and of course, the recorded Survivor was pixellated and choppy - unwatchable.
So, between when we left the show and came back about an hour later, the reception for that channel went south, then came back to pristine....