Might be as simple as the source. If some channels look good and others don't, it may be that the signal the satellite is retransmitting is simply poor. You may notice more when you have a larger/better resolution TV b/c your frame of reference has changed. Another possibility is that, if you have a multisat system, you may be receiving one satellite better than the other. I don't know whether you have, like DirecTV, SAT A, B & C or not.
Beyond that, might be some issue as to the way the TV is upconverting the signal. You might want to try the gurus on www.avsforum.com or see if there is a thread there on your particular Tosh.
Beyond that, might be some issue as to the way the TV is upconverting the signal. You might want to try the gurus on www.avsforum.com or see if there is a thread there on your particular Tosh.