Just had a new multiroom install last week and have been suffering from terrible pixelations on HD channels, some unwatchable. Tech came today and checked it over and sorted out within minutes. The point where the cable came into the house had a very strange splitter set up added when the old NTL install was done. That was completely removed and a powered signal booster added on indoor end as 'belt and braces'. Problem solved, now excellent picture on all channels, (and much increased internet speeds too), in fact much better than my previous Sky install. I think the original install guy was a bit inexperienced and didn't check the incoming coax signal as it was waaay below the threshold. He did a good job but should have checked this thoroughly. Didn't get a chance to check all channels before he shot off!