By HANS LAETZ
City News Service
Friday's confusing switch by U.S. television broadcasters from analog to digital television is even more confusing in San Diego, where Mexican and low-power TV signals, and channels flitting in from Los Angeles, complicate the matter.
The rest of the nation is set to see its old analog signals retired Friday, part of the nationwide shift in technology that will free up giant chunks of electronic space for new wireless services.
But four of San Diego's six most-popular channels have already made that switch. Only channels 39 and 51 still offer analog feeds broadcast over the air - signals that will cease on Friday.
Several San Diego stations will abandon their longtime electronic homes as they shift to new digital assignments in the UHF band. But to make it easy on viewers, the new digital channels have encoding devices that tell digital TV sets and converter boxes that they are actually watching the old TV channel number.
Adding to the confusion, some digital stations will move their digital signals on Friday to new homes. KUSI-TV, for example, will not only shut off analog channel 51 but will move its programming to digital channel 30, the FCC said.
That means people who use off-air antennas for KUSI, which calls itself Cable Channel 9, will need to use the rescan feature on their TVs or converter boxes to regain its programming after the switch.
And for some people in the back country, canyons or buildings where TV signals have always been a bit dodgy, the switch from analog to digital will mean an end to free, off-air television signals. That's because a few TV stations are slightly moving their antennas, causing a subtle shift in coverage areas.
Other may get better signals. Several California stations are increasing their power now that nearby stations are abandoning their old analog homes.
Tijuana stations are not required to shut off their analog signals, and have no plans to do so. Some Mexico stations with English programming, such as XETV channel 6, do offer digital transmissions from Baja California for their San Diego viewers on a different channel.
If this is confusing, remember that all these actual transmission numbers are quite irrelevant. Every digital-ready TV set, and digital converter box, sold in North America has the built-in ability to scan for available signals, and convert the data into familiar channel names such as channel 8.
And as anyone who has set up a digital off-air receiver knows, digital TV suffers from the
cliff effect,'' where the signal will go from perfect to digital mush without any intermediate steps.
Old analog signals simply gave the TV set a ghost or some static when their signals dipped. But digital TV translates a lousy signal as bad computer data, and starts breaking up and "tiling'' the picture as scenes change.
But most of the viewers in the San Diego television market, who could get acceptable analog pictures up until Friday, will now get digital coverage, the FCC predicts. And that comes with advantages, such as high-definition signals and multicasting.
Some channels are taking advantage of the change to offer up to 8 TV signals wedged onto its digital channel, such as foreign language offerings.
Some PBS affiliates are offering 24/7 kids programs.
And many network affiliates are using most of their digital spectrum for high-quality local feeds of their newscasts and network programming. But they have also launched new lifestyle and all-weather forecast channels on their digital signals.
Despite oversimplified explanations from the FCC, some satellite TV customers will need to rescan their set-top boxes after Friday as well. HDTV reception for some boxes is obtained not via satellite, but via over-the-air signals, even though the HDTV channels are mixed in on the satellite box TV guides.
And persons owning wide-screen TV sets and using antennas will need to rescan after Friday, as their built-in digital tuners will need to scan the skies for the new channel assignments for some stations.
Friday's changes are historic. For example, the channel 5 frequency used by KTLA television in Los Angeles since it signed on the air in 1947, and regularly pulled in by many San Diegans, will go to full-time static after Friday.
KTLA will be transmitting only on its channel 31 assignment starting Friday, a channel it has been using for its digital feed for several years. Many viewers in San Diego County are able to pull in some of the 22 Los Angeles television stations using their digital tuners.