I have been having this exact same problem for months now. I have called DTV about 5 times to complain and all they have me do is re-set the receiver. When I called this past Sunday to complain again, I told them I wanted this resolved once and for all. My problem involves all of the local HD channels. I live in the NY area (North Jersey), so I get CBS HD on 80, NBC-82, ABC-86 and Fox 88. It happens on all of those channels very consistently every night. Sometimes it will be fine then all of a sudden, pixelization and sound drop outs. Not a cloud in the sky and all this BS happening. I finally told the girl I have had it and want it taken care of. They said they will set up a service call and take care of it. In fact, as I type this, I am waiting for someone to arrive. They told me WED 1/10 between 4 and 8PM. I am ready to give up DTV and go over to Cablevision. It is BS that I am paying for HD and can't use it. I have to switch over to the regular channels so I can watch and listen without the dropouts.
Frustrated in New Jersey!!!!!!!!!!!