My local cable company(comcast) now offers local stations(network cbs, nbc, pbs, abc, Fox is coming soon) in HiDef. I am a satellite subscriber(Directv)so have some channels in HiDef, but not network channels. So I used my attic antenna for local HD. I just installed(I already had basic cable)Comcast's HD receiver at 5 bucks per month. So really do not need attic antenna anymore. It was somewhat flaky even though it was a large Channel Master Bow(4228) with a remote controlled rotator. I was in a horrible area, 45 miles away, behind a hill and in the attic. All is well now. An antenna and a rotator will cost you a couple hundred bucks which is 40 months of rental on the HD box. In fact any HD box for sat or off the air will cost you a few hundred dollars so if you are a cable user, this might be the way to go.
I did have a problem putting the DCT 6000(HD Comcast/Motorola box) on my Mx 500 as I was trying to use in a Device Button position other then what was originally the cable box position(position 10--I was using this spot for my Sony Sat HD box). Moved things around and all is well now. Had several posts on this and still do not know why could not use other device positions for this device.