How do the HD channels appear?
Stations use multi-casting. The HD channels will actually appear as suffixes to the existing FM stations. For example, if your local radio station (let’s say 97.9) is also broadcasting in HD, you will see 97.9, 97.9-2, 97.9-3, etc. Each radio station can multi-cast up to four HD channels. They might have one for rock, one for country, one for news and one for sports, for instance. You will never see them if you are in regular AM or FM mode but they appear as soon as you tune to the HD-AM or HD-FM band. The station that is broadcast in normal AM or FM mode is also broadcast in HD-AM and HD-FM, so once you are using the HD bands, there really is no reason to switch back to the normal modes.
