Radio stations are changing from analog to digital, and when they do, they have the ability to broadcast more than one channel of content on their frequency. These second and third channels are called "HD."
You need a special HD radio tuner to listen to HD radio. You can read more about HD radio here. And you can read about and purchase HD radios in the Echoes technology store, where every purchase supports Echoes.
Most Echoes stations are simulcasting their main service on their first HD channel. In addition to hearing Echoes on these HD channels, you can also tune in to Echoes on the second HD service of several stations around the country. We've listed these HD stations both in our complete station list and a separate HD station list.
Echoes on HD Radio (note: these are stations that broadcast Echoes ONLY on one of their HD channels or in a different time slot than on their main channel. Most Echoes stations simulcast their main signal on an HD channel as well)