I am having some issues with some of my channels, when I compare to my working channels the BER is really high on the dodgy ones, where the working ones are like 20.
Try checking that your cable connection is tight. Also try taking all splitters out and running straight off the feed. I had this problem a while back with bravo 2 and five. The feed into the tuner had splayed out. Crimped it tight and sorted the problem.