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Cable Doesn't Mean Perfect Reception


Question: I have Adelphia cable. Although most channels come in clearly, some local ones--particularly KCBS-TV Channel 2--are very grainy and look like I'm picking them up with a standard rabbit-ears antenna. Why don't all channels come in equally clear?

Answer: Cable TV services originated in 1948 as a "community antenna," bringing remote TV signals into rural areas that couldn't tune in to over-the-air broadcasts. Although the technology has improved dramatically since then, the basic principle is the same: The cable company collects a bunch of TV signals at its central office, or "head end," then pumps them through wires to customers' homes.

Adelphia historically has received local TV programs via microwave, or high-frequency, wireless transmissions sent directly from the stations. That technique delivers a more reliable and higher-quality signal than a conventional TV transmitter, but it still can be affected by unusually bad weather or electronic interference from large motors.

"Off-air broadcast reception has always been a challenge," said Lee Perrin, a spokesman for Adelphia.

That's why the company is starting to install fiber-optic connections to the local stations, which would deliver clearer signals, he said.

Switching to fiber optics won't necessarily solve your problem, however. That's because the picture quality on Channel 2 may be affected by problems on the wires running from the head end to your living room.

Those wires are broken into many segments, and poor connections or aging equipment at each juncture can degrade your picture.

Inside your house, breaks or weak spots in the insulation around a cable could allow Channel 2's over-the-air signal to seep into the wire, causing "ghosts" and other distortions in the picture. So could problems with the insulation around your TV tuner.

KCBS and Adelphia say they haven't received other complaints from your community, so it doesn't sound like the problem is at Adelphia's head end.

It's more likely on the line between the utility pole and your building.

You might try running new cables from the wall to your cable converter box (if you have one) and to the TV set, making sure all the connections are tight.

If that doesn't help, ask Adelphia to inspect the cables outside your building.


Jon Healey covers the convergence of entertainment and technology. He can be reached at Submit questions to Please be specific about your problem and include a daytime phone number.

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