If you are getting channels 2-72, then you have the cable plugged into the NTSC port on the HVR-1600 which only pulls in standard definition cable. The other coax port is for ATSC which can pick up ATSC over the air HD channels as well as clear-QAM digital cable.
Thanks for the advise. I am now able to see hundreds of QAM channels. Of course, most of them are either repeats of regular channels, or are of no interest, or are channels with no signals. My problem now is that I can find only one clear HD QAM channel (my local FOX channel). There should be at least six more clear QAM HD local stations, but I can't find them.
Do you think that the cable provider (Astound Broadband) would give me the QAM channel IDs if I asked nicely?