Weird. Since it's only happening with one particular channel, then it's got to be something with the SA HD Box, not the TV. The TV doesn't know what channel it's on, it's just getting a signal from the cable box. What channel is it?
Maybe do an experiment - move the SA HD cable box several feet from the TV and see if the channel still gets pixelated when you get near the TV or if it only happens when you're near the cable box.
Weird. Since it's only happening with one particular channel, then it's got to be something with the SA HD Box, not the TV. The TV doesn't know what channel it's on, it's just getting a signal from the cable box. What channel is it?
Maybe do an experiment - move the SA HD cable box several feet from the TV and see if the channel still gets pixelated when you get near the TV or if it only happens when you're near the cable box.