I am experiencing the same problem with all the HDTV stations with the OTA antenna. They were all working fine Sunday morning and then they all went out Sunday afternoon. Standard stations work fine.
I did a signal check and they are all above 83%.
I have a direct antenna hook-up to the 50" Panasonic using terk -55
I have a Hitachi 42HDS69 HDTV, pretty basic setup (no audio receiver, no cable box, just a DVD via the HDMI) with an outdoor antenna feeding into the antenna jack. I get great picture on all local OTA broadcasts, but frustratingly, no audio on three of the HD channels in my area: CBS, ABC, and UPN. It wasn't always this way but these channels have been sound-less for several months now it seems. Audio is fine on all the other HD channels.
Anyone have any clues as to whether this could be a problem with my set or is it with the tv station? It would seem highly improbable that three separate tv stations would have no audio track and for so long. At the same time, why would my set only have this problem with three of the HD channels and be fine with the others? I am stumped.