I just purchased the Series 2 Dual Tuner TiVo brand DVR and had been noticing static/scan lines on many channels. Most channels seems acceptable, though a series of channels (mostly sports, ESPN->FSN) have a heavy static to them while others have intermittent scan lines that run through the picture. Connecting coax straight to the TV has a clear signal, so, after reading many posts, it seemed like installing a video signal amplifier would help out.
I bought an RCA 10 db amplifier. When I connect coax straight from the wall, to the amplifier, then straight to the TiVo, the TiVo receives the signal (though it actually gets grainier) - however when I plug the amplifier in to start getting the power boost, TiVo loses the signal and goes to the lost signal blue screen.
10 db seems to be the lowest amp I could find - I'm just wondering if anyone has any hints, since everyone's first suggestion with grainy/staticy picture is to try a 10db amp.