Originally created 03/09/02

Sun could be disrupting your cell phone



That glitch in your cell-phone reception just might be due to a sunspot, according to researchers studying the effects of solar bursts on our wireless connections.

"This is the first time this kind of effect has been recognized as a problem, but we've only had a lot of wireless phones out there for the past five to seven years, less than one (11-year) solar cycle," said Louis Lanzerotti, a researcher at Lucent Technology's Bell Labs in Murray Hill, N.J., and co-author of the study published Thursday in the journal Radio Science.

Bursts of radio signals come from the sun during solar flares, which emerge from sunspots, and frequently disrupt some technologies. Lanzerotti and Dale Gary, an associate professor of physics at the New Jersey Institute of Technology in Newark, looked back at 40 years' worth of records on the disturbances to calculate how often the signals reaching Earth are strong enough to fuzz up cell phones.

Gary said that the latest calculations, yet to be published, suggest that wireless phones might be blitzed somewhere on the planet as often as every 3 1/2 days when the sun is in its most active period, the latest of which is just winding down now.

At the lowest-activity period for solar storms, events occur every 18 1/2 days, Gary said.

Information about the radio bursts came from observations collected by the National Oceanic and Atmospheric Administration, which also monitors space weather. The first detection of radio signals from the sun came by accident during World War II, when bursts at much lower frequencies muddled some of the earliest radar devices.

"Whenever we come up with a new technology, we have to assess what natural phenomena might affect it, which often come in some surprising ways," Lanzerotti said.

"We're hoping that our research will help equipment makers and service providers build in technology that can work around these sorts of disruptions, particularly in the next generation of equipment that's going to use a broad band of radio signals."

Gary said the solar bursts are most likely to disrupt calls in areas already having spotty reception, and that antennas pointed east or west during the morning or evening are most susceptible.

"This probably isn't going to be a problem across an entire system, but if a receiver is looking directly at the sun low on the horizon when one of these bursts occurs, that's when you're going to get the most noise," he explained.

Since energy from the sun hits Earth at the speed of light, there's really no way to warn of bursts in advance, Lanzerotti said. "The signals come in, and then we see the flare."

Satellite sentinels in space do give NOAA's Space Environment Center in Boulder, Colo., advance notice of some slower solar phenomena that can disturb satellites and other types of systems on Earth, such as magnetic waves.

"The research looks very reasonable to me, that if the sun's in a direct line with the transmitter and the user, there could be disruptions," said Joe Kunches, chief of space weather operations for the NOAA center. "But there are a lot of things out there that cause calls to be dropped, and the sun may not stand out among all the suspects.

"I'd hope that this study would encourage some service providers to look at what happens to their transmissions during some of the events in the future," Kunches said. "Right now, other than some general forecasts we give about the radio environment from solar X-ray emissions, there's not much we could offer to forecast conditions that might affect cell phones."

Gary agrees that most cellular customers don't care why they lose a call, they just get annoyed when they do.

"But some people who use cellular connections for life-or-death communications might pay at least some attention to these problems, and maybe consider rerouting their calls to more secure lines during the sun's busier times," he said.

On the Net:

http://www.agu.org

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www.njit.edu

www.sec.noaa.gov