Dave,
Seems you are trying the best way to find out before you but. Here's a little of what I was able to find out from the net. I don't have a HD radio so I can't check for you.
http://www.hd-radio-home.com/hd-radio-signal-coverage.html It's here, but can you hear it?
One of the most frequent questions we got has to do with HD Radio's signal coverage.
From what we have been able to learn to date, a station's HD Radio signal should be just about identical to its conventional, analog AM or FM coverage. There will be areas where you will be able to hear only the analog signal and areas where you will be able to hear only the HD Radio signal.
Notice we said "should be just about identical." This is because some sources say this just isn't true. "We were told back in the beginning that the HD coverage would be equal to the analog signal," says Robert Conrad, respected owner of WCLV-FM. "Unfortunately, the industry is now finding out this is not the case, that the HD coverage is considerably less, something like 60% of the analog coverage. We've also found that even in a strong HD signal area, a dipole antenna is required."