Satellite radio was introduced roughly ten years ago and has changed dramatically since the original introduction of the Delphi Skyfi. The most significant change is that SiriusXM is now built into many vehicles. However, you might be surprised at how many standalone units are still in use. The latest models include the Onyx, XMp3i, and the extension of the Stratus, Sportster and StarMate lines (they are up to the sixth generation).
The standalone models all require an antenna to be mounted within the line of site to the satellite. Many customers are under the impression the antenna must be mounted on the roof outside the car. That’s not the case. The antenna works quite effectively within the car as long as it is mounted where it can see the sky.