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Blame the equinox. The sun's radio waves can overpower cable satellite signals, which send a garbled message back to earth. Snowy TV screens result.
By BRIDGET HALL
© St. Petersburg Times, published March 1, 2000
INVERNESS -- Your TV screen flickers, then turns snowy for a few minutes before fading back into regularly scheduled programming. You might not realize it, but the sun has just tried to beam itself into your TV set.
Cable television providers say the next two weeks might be peppered with brief moments of solar interference, caused by the sun's radio waves overpowering satellite signals. They say the disruptions will be minimal, lasting anywhere from a few seconds to up to 30 minutes, and their only advice is to be patient.
"By the time you get up to go to the bathroom or get a soda and come back, (the program) will be back on," said Frank Cline, technical operations manager with Adelphia Cable Entertainment.
The sun can interfere with satellite transmissions twice a year, as the sun nears the equator for the spring equinox March 21 and the autumnal equinox Sept. 22.
The interference this year will be at its worst, scientists say, because the sun is at its peak period of activity in its 11 1/2-year cycle.
"We're seeing more movement of sunspots, stronger magnetic fields and more solar flares," said Joseph A. Carr, former director of the planetarium at the University of South Florida. "All that means there's a greater effect on the earth."
Most cable and telecommunications satellites are stationed more than 20,000 miles directly above the earth's equator, a geographic reference point that makes it possible for receivers on earth to find the satellite and pick up on its signal.
As the sun approaches the equator, it can come in line with a satellite. The sun's radio waves overpower the satellite's signals, which send a garbled message back to receivers on earth.
The phenomenon affects anyone taking a feed from the satellite, although the timing varies slightly by region.
Here in Florida, cable officials say the disruptions could happen any time between 1 and 5 p.m. from March 2 to March 14, when the sun is at its peak.
Ray Graber, spokesman for Time Warner Communications, said disruptions could be more severe from March 4 to March 10, with only minor interference in the days just before and after.
The interference only affects the premium cable channels, not local affiliate stations, whose broadcasts are transmitted by antennae. The disruption could affect different channels at different times, depending on which satellite is in the sun's path.
"There's nothing we can do about it," Graber said with a chuckle. "The sun is more powerful than anything."
University of Florida astronomer Francisco Reyes said even with the sun at its most active period in this 11 1/2-year cycle, the sun still oscillates between days of high and low activity.
"How bad will it be? That's hard to tell," Reyes said. "It really depends on how active the sun is on that particular day."
In theory, solar interference could disrupt other satellite communications, such as those transmitting cellular pages or international calls, but telecommunications officials say there's no cause for concern.
"Most of the satellites now are so sophisticated that we don't experience disruptions like that," AT&T spokesman Dave Johnson said.
Even if there were a problem with a satellite, Johnson said, the effect would be minor because most telephone traffic, including 98 percent of AT&T's domestic calls and two-thirds of its international calls, run through fiber optic cables.