Do I have to subscribe to a service?
No, unlike satellite radio — which is analogous to a paid cable TV service — HD Radio is free and transmitted over the air. You just need to have an HD Radio.
That’s where the marketplace is still catching up with the technology. Although you can buy HD Radios in some retail outlets or on the internet, there aren’t that many sets out there yet. And you want to be sure to get not just an HD Radio receiver, but one that can get multiple channels… besides the improved sound, the multicast capability of HD is its biggest benefit.