Are you sure about QAM. The user manual states clearly it has QAM. The Tuner section is the exactly the same as xx88. Manuals are available at Samsung's web site.
I should receive the delivery tomorrow and expect QAM will be there.
My understanding is the clear digital channels are mapped to TV channels below 135. For example, the partial line up in Houston area:
78-1 Hallmark Channel 480i
78-2 Golf 480i
78-3 MSNBC 480i