I am having the same issue I think, does it sit there for a while before if says no signal? It will be ok one day, then next day half my recordings are stuffed. The recordings are there but they can not be played, comes up with Video error, and preview window is ether blank or white with what looks to be red interlaced / corupted text at the top!
Using 2x FusionHDTV DVB-T PLUS cards