Not sure if i have the right place to ask this question but I have a pioneer elite HD tv, about 4yrs old and when i had comcast cable tv i would get mico blocking on hd channels once in awhile, where the picture would go crazy little blocks ect and sometimes lose audio, now i have directv and same thing, is this due to weak signal from like abc, nbc, cbs ect or what, no one can find problem.