I receive my locals through OTA antenna so I can watch them in HD. Yesterday my local CBS affiliate listed in the EPG changed from 10-1 to 56-1 (which is their official digital number). Yet when I tune to 56-1, it's a blank screen with a "searching for signal on off air tuner" message. The channel banner at top of screen shows the proper channel information, but on a blank screen. I tried resetting the receiver and rescanning OTA channels and nothing works. Called Directv and they didnt seem to know what the problem was. Anyone ever experience this?