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Satellite radio:how does it work?

QUESTION: In the March/April issue of Land Line, I read Paul Abelson’s article on the new radio system that is out now. I was happy to read about this wonderful invention in depth. Paul stated at the end of the article that if there were any questions to ask then ask. I would like to know more about how it works. Where would I find out the technical side of how these are made? How they are put together? I want to know how the sending and receiving gets done through the radio satellite. I am a technical person, and would like to curb my curiosity. —Carol

ANSWER FROM PAUL: Thanks, Carol, for your interest. I am a technical person, too, but mostly with mechanical things. If I can see it, I usually can understand it. I can see engines, fuel systems, transmissions and filters, but I have trouble seeing electrons. My knowledge of what electronics do is reasonable, but I am weak on the “how” behind the “what.”

That said, here’s what I do know. Digital signals fed by satellite to radio and TV/cable stations all across the country are captured by receivers at XM and Sirius studio locations. Each service also creates its own original programming, music arangements, news and commentary. All these signals are transmitted to each of the services’ solar-powered satellites in orbit above the United States (Sirius) or above the equator (XM). The signals are amplified and re-broadcast to earth, to be received by the specialized equipment described in the article and enjoyed by us.

One service advertises, “Beyond AM. Beyond FM. Now, there’s XM.” AM and FM are both analog systems. XM and Sirius are both digital. I suppose AM is like listening to old vinyl phonograph records, FM is like tape recordings and satellite digital is like listening to CDs or DVDs.

This is probably too oversimplified if you are a technical person, but it’s the best I can do with electronics. Next time, try me with ABS. I’m much better with the mechanical stuff.

You might try each service’s web page. Check Delphi’s site, too.

—Paul Abelson, technical editor