Many HD Radio stations now are broadcasting additional digital channels called HD2/HD3 channels. They are all subscription-free. This is basically multicasting that allows stations to broadcast multiple channels on one frequency. With Multicasting through HD Radio technology, radio stations can offer their listeners a variety of options. Plus, these stations can offer their advertisers more options for reaching various audiences. HD2 and HD3 channels generate more revenue for radio stations. Some broadcasters are using the additional channels to extend their current brand and format. Others are using these extra channels to cash into an unknown, lucrative territory by creating unique and compelling content that has never been heard before on the radio. More and more stations are using these extra channels to provide a unique coverage of music, sports and other niche programs to their listeners. Incidentally, HD Radio technology allows better audio and exclusive unique content choices. One major benefit of HD Radio technology is its sound quality. It is dramatically better because of the digital transmission. I learnt a great deal about it on this particular website. Surf the site to know more!