The differences between satellite radio and HD radio: HD radio is not being issued in "high definition", I think the term is rather HiFi Radio, where audio quality is significantly better than the current emitted by FM or AM band. This for a person living in Europe or Latin America may sound to Chinese, mostly because neither the satellite nor radio "HD radio" has come to any country.
The quality of radio in almost any country is the same as 20 years ago, something we're missing. But David Pogue explains the basic differences between these two systems. First, the HD Radio is free, satellite radio is subscription payment, offer same stations wherever you are, by contrast, HD Radio, despite being most free and without ads (how they earn money?) Depends on where you are to receive the stations. Another possibility is HD radio with extra bandwidth, are able to emit up to three stations in the same frequency, usually by the same production.
In short, HD radio allows canned sound fidelity, a free service, but is limited by its antenna and the coverage they have, instead of satellite radio gives you the same quality, hundreds of radio stations wherever you are (in USA) but under subscription.
