I am in the same boat... I was getting my local NBC on 10-1 perfectly fine before the switch and now after Feb 17 I cannot get NBC at all. This really upsets me because I watch so many shows on NBC and I have missed all of them since Feb 17.
God only knows how long it will be before this is fixed. I am one PO'ed customer right now.
I live in a small DMA #154 Rochester, MN so I do not expect this to be solved soon and the worst thing is that I keep wasting time resetting my OTA hoping it is fixed. A Big waste of 10 minutes each time.
How do you join an Antenna?
I have a Channel Master 7777 Preamp which has both UHF and VHF inputs. I have ordered a Winegard YA 1713 VHF-Hi antenna to help with KTTC and I'll plug that into the VHF input while my Channel Master 4221 will be plugged into the UHF input. From looking at your antenna (Antennas Direct DB2), it is a UHF only antenna. My 4221 is similar to yours, but mine has 4 bowties (with the preamp) and I barely get 10-1. BTW, I'm in NW Rochester on high ground and my antenna is in my garage attic aimed out the gable with no roofing material in the way.
It is possible that your HR20 does have the new channel 10 mapping, but it may be too weak. Just curious, how good is your signal with KAAL, KIMT, and KYIN?
Here is a great link to a Rochester HDTV forum: