I tried it... and I remain hopeful despite not being able to get it working.
First of all, I have the HP Expresscard tuner (2nd edition that has QAM tuning), which is itself a rebadged Hauppauge HVR-1500. That card is not on the list of supported cards for this QAM driver.
However, I thought there was a decent chance it would work, and at least until the last step of their walkthrough it does. I followed the directions to a T (including installing the latest driver packaged with the QAM utility). I then re-set up the tuner as ATSC only (it's a hybrid, not a combo) and then launched their nifty 10-foot QAM scan utility. It scanned through all my channels and locked 41. At the end of the scan it prompted to restart, and according to the walkthrough that is supposed to "enable Clear QAM mode in the driver".
However that is the end of their instructions. After reboot there were no channels added to my guide (it just had the default ATSC list, none of which worked because an antenna is not connected). I assume the next step is mapping the 41 found QAM channels to ATSC guide listings but I am unaware how to do that--there are no further instructions and I have found no other posts from people who have attempted this.
I'll keep playing around in the TV options... maybe there's something I am missing... and maybe you truly do need a 1250, 1600, or 1800 to be able to do this. But the fact that the scan utility found the QAM channels using this card makes me hopeful that it will work eventually.
If anyone has any info/advice, please post! Thanks.
Dan