HD radio is a free service provided by stations that have upgraded to the technology that allows listeners to experience almost CD grade reception over the airwaves. It requires an HD radio receiver, which can be purchased from most electronic stores or online. HDradio.com has links to a wide selection of brands and models for use with vehicle radios or at home.
To find participating station for a specific area, the HD radio website also has searchable listings by city and state. HD radio differs from satellite radio, as it allows stations to broadcast over AM and FM airwaves and doesn't charge a monthly subscription or control what is being broadcast.