I have noticed on a couple of channels I receive on the AM21 that I am getting searching for signal on the off-air tuner...(792) for the .1 channel but i receive the .2 fine. For example 13.1 is cbs with 13.2 being mytv. I can't tune in CBS but mytv comes in fine. Same thing with channel 21.1 which is the CW in HD it won't come in, but 21.2 which is the CW in SD comes in fine. The AM21 is connected to a HR22-100. Any suggestions?