February 1, 2007

1 min read

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Working Knowledge: Satellite Radio—Song Beams

By Mark Fischetti

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Satellite radio can send the same 100 channels of music, talk and sports to you at any street corner in the nation. Yet someone next to you may receive a different set of channels, and a third person who does not subscribe cannot pick up a thing. How can the service blanket the country yet be so discriminating?

Three companies provide the world's satellite radio: XM Satellite Radio and Sirius Satellite Radio for the U.S.; and WorldSpace for Africa, Asia and Europe. XM uses two geostationary satellites and about 800 low-power ground repeaters scattered around cities where tall structures can block the satellites' line of sight. Sirius has three birds in highly inclined, elliptical orbits and about 100 high-power repeaters, each bathing a metropolitan area. Both architectures provide equally reliable service, says Dan Goebel, a senior research scientist at the Jet Propulsion Laboratory in Pasadena, Calif., who previously designed amplifiers for ground repeaters.

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Mark Fischetti was a senior editor at Scientific American for nearly 20 years and covered sustainability issues, including climate, environment, energy, and more. He assigned and edited feature articles and news by journalists and scientists and also wrote in those formats. He was founding managing editor of two spin-off magazines: Scientific American Mind and Scientific American Earth 3.0. His 2001 article “Drowning New Orleans” predicted the widespread disaster that a storm like Hurricane Katrina would impose on the city. Fischetti has written as a freelancer for the New York Times, Sports Illustrated, Smithsonian and many other outlets. He co-authored the book Weaving the Web with Tim Berners-Lee, inventor of the World Wide Web, which tells the real story of how the Web was created. He also co-authored The New Killer Diseases with microbiologist Elinor Levy. Fischetti has a physics degree and has twice served as Attaway Fellow in Civic Culture at Centenary College of Louisiana, which awarded him an honorary doctorate. In 2021 he received the American Geophysical Union’s Robert C. Cowen Award for Sustained Achievement in Science Journalism. He has appeared on NBC’s Meet the Press, CNN, the History Channel, NPR News and many radio stations.

More by Mark Fischetti
Scientific American Magazine Vol 296 Issue 2This article was published with the title “Song Beams” in Scientific American Magazine Vol. 296 No. 2 ()
doi:10.1038/scientificamerican022007-2ZCssfPUUBDKyvv7JXZVOs
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