Radio Poised for High-Tech Leap
Digital satellite radio can beam high-quality sound to large global regions
TWO days before Christmas, almost 60 years ago, an inventor and a businessman drove from Rockefeller Center to a small laboratory at Columbia University in New York City. Carefully laid out in two rooms were tables of vacuum tubes and circuits.
When the inventor, Edwin Armstrong, switched them on, out came a wonderful thing: radio with no static. The demonstration marked a great technological leap. Modern frequency modulation or FM radio was born. The year was 1933.
Radio's next great technological leap may have occurred on Dec. 2, 1991, when National Aeronautics and Space Administration (NASA) engineers and reporters climbed into a Dodge van, drove around Washington, D.C., and listened a radio broadcast that sounded as good as a compact disc. The secret? The signal was digital, instead of analog, and came directly from a satellite.
If the technology - called digital satellite radio - catches on, it will change the landscape of radio.
While television offers national broadcasts through networks and superstations, radio remains primarily local. At best, the most powerful amplitude modulation (AM) stations may be picked up halfway across the United States on a good night. Shortwave radio is even more at the mercy of atmospheric conditions.
Digital radio broadcasts by satellite would change all that.
A single satellite in orbit could beam messages to an entire country or even a continent. A dozen such satellites linked up could broadcast to the world. Since a satellite beam can be split up into separate beams, or even beams within a beam, broadcasters would be able to target audiences geographically.
It's "an emerging global radio market," says Pat Clawson, Washington bureau chief of Radio & Records, a trade publication.
"It gives the broadcaster a whole new world of programming that he never had before," says James Hollansworth, program manager of direct satellite broadcast at the NASA Lewis Research Center in Cleveland. "He's got a bigger audience to look at."
The idea of direct satellite broadcast has been around for years. Ships have long carried big antennas to communicate by satellite. The challenge of commercializing the technology has been to build a cheap, portable receiver - a satellite dish that fits in your pocket.
In their demonstration in December, researchers at the NASA Jet Propulsion Laboratory (JPL) in Pasadena, Calif., used a low-power Inmarsat satellite, which broadcasts to ships. The low power forced the engineers to equip the van with a sophisticated round antenna about 1 foot wide.
In a commercial system, a broadcaster would boost the power of the satellite and make the receiver much smaller and less expensive. Dr. Hollansworth says he believes that engineers will be able to build a receiver the size of a Sony Walkman at an initial cost of about $300. Mass-production could push the cost down to about $50, he estimates, if the technology catches on.
The technology got a huge boost last week when the World Administrative Radio Conference (WARC) recommended that nations allocate the L-band - 1452 to 1492 MHz (megahertz) - of the radio spectrum for digital audio. Of the 127 nations represented at the conference, only the US, the former Soviet Union, and India took exception. They plan to broadcast in a higher part of the spectrum called the S-band (2310 to 2360 MHz).
Even though the US will broadcast at the higher frequency, which requires more power and entails higher costs, proponents of digital satellite radio are pleased with the WARC decision.
The biggest boost was that the WARC did not implement a phase-in period, says Martin Rothblatt, chairman and chief executive officer of Satellite CD Radio Inc. in Washington, D.C. If the Federal Communications Commission grants the company a license by the end of this year, Satellite CD Radio will be ready to launch satellites for digital broadcasting by 1995.
Not surprisingly, many existing radio stations in the US are resisting the technology. One committee of the National Association of Broadcasters is proposing that radio broadcasters appropriate digital technology and beam it from earthbound stations.
Beaming the signal from Earth would offer listeners the CD-quality but not the range beyond today's television or FM radio stations. That idea is much less threatening to territory-minded radio broadcasters. The European Community's digital-radio plan, called Eureka-147, envisions this kind of system.
That a spectrum allocation was recommended at all by the WARC is a big boost to the technology. Now, countries can make their individual allocations of spectrum and begin building devices. The European Community's Eureka program has concentrated on broadcasting CD-quality sound from Earth-based towers. The US proposal envisions not only satellite broadcasts, but also a range of sound qualities from the equivalent of AM all the way up to CD.
ONE advantage of broadcasting by satellite is that it offers considerable flexibility. A satellite can offer new radio channels to an entire continent, or it can target those channels more narrowly. It can offer various qualities of broadcast sound.
By using lower sound qualities, a satellite can beam more channels. For example, a satellite broadcasting at 1500 MHz could derive 60 CD-quality channels, 300 FM-quality channels, or several hundred AM-quality channels.
Satellite-generated AM channels might be just the ticket for developing nations that don't have a sophisticated broadcast network, Hollansworth says.
Some critics of the American S-band plan say that developing nations may get a 10-year jump on the US. Broadcasting at L-band is anywhere from 25 percent to 50 percent cheaper than broadcasting at S-band, according to NASA's Jet Propulsion Laboratory. Also, developing nations don't have as many L-band services to relocate. The US didn't want to broadcast digitally at L-band, because the Defense Department uses that part of the spectrum for its own purposes.
Shortwave broadcasters are also interested in the technology. The Voice of America cosponsored the NASA tests last year. Digital satellite radio could not only target international broadcasts more effectively, it could end up being cheaper too.
To air a CD-quality program to a 1-million-square-mile region at S-band would cost from $100 to $200 per hour, estimates Dr. Nasser Golshan, system engineer for NASA's JPL program. Just the electricity costs of shortwave systems can be more than that.
"The only catch is ... people have to have the radios," he says.