Digital age giving stations mixed signals.

KTTV in Los Angeles is better known as FOX 11. Its station logos, on-air signoffs and Web site address all emphasize the station's network affiliation and placement on the dial--not its call letters.

FOX 21 or FOX 43 just wouldn't have the same ring.

Yet the station, like dozens of other stations nationwide, now must struggle to cling to its position on the dial because of signal conflicts identified during the planned transition to digital broadcasting.

KTTV and another L.A. station, public broadcaster KCET-TV (Channel 28), have about a month to correct "impermissible interference" that the Federal Communications Commission said would occur when stations switch to digital signals in 2007.

They are among 166 stations nationwide that have to weaken their broadcast signals, surrender their position on the dial or persuade a neighboring station to do the same.

The sweepstakes for dial positions carries enormous consequences. Not only will some stations be bumped to unfamiliar spots, but those pushed to the upper ends of the broadcast spectrum face whopping increases in their electric bills because the higher frequencies require more power to reach the same geography.

The already crowded broadcast dial in major cities will be reshuffled as part of the transition from analog television to digital, which is expected to occur in the next four years.

Interfering with San Diego 

Currently, 1,500 U.S. stations broadcast in both analog signals on their original frequencies and a companion digital signal on a higher frequency. Most stations have petitioned the FCC to reclaim their original frequency when they go all-digital, but the reallocation of frequencies--and the different characteristics of digital signals--are causing conflicts.

In the case of KTTV, which has asked to keep Channel 11, its signal would bleed into the adjacent Channel 10 occupied by KGTV in San Diego, the FCC said. KCET's request to stay on Channel 28 would conflict with signals claimed by KFTR (29) in Ontario and KEYT (27) in Santa Barbara.

KTTV and KCET declined comment beyond saying they were aware of the problem and would attempt to correct it.

In analog broadcasting, adjacent signals may bleed into one another slightly but still be watchable. In digital broadcasting, the conflicting signals pose a larger problem--the viewer either gets a clear picture or no picture at all.

The FCC is encouraging stations to come up with their own solutions--either by weakening signals, realigning transmitters or bartering frequencies. In some cases, however, the FCC will have to impose a solution.

"We do expect it to be an orderly process," said Rick Chessen, chairman of the FCC's digital television task force. "We're going to make every attempt to give (broadcasters) at least the same opportunity to serve the same service area they had in the analog world."

As part of the switch to digital, the FCC is compressing the broadcast spectrum from 68 channels to 50. Channels 52 to 69 will be auctioned off to digital broadband companies and turned over to emergency-services agencies. Broadcasters currently operating on those channels are applying for signals in the truncated broadcasting range. Those include seven stations in the L.A. metropolitan area, none of them major network affiliates.

The scramble for channels could bump dozens of stations nationwide from signals they have been using since the advent of commercial television. In many cases, though, the issue is academic because an estimated 85 percent of television viewers nationwide get their signals from cable and satellite, which are not affected by the reallocation of broadcast space.

Even among broadcast viewers, new technology allows stations to "trick" television sets into picking up the signal from a different channel. That means a viewer could select Channel 4 on his remote control but the television would automatically find the station's signal on Channel 20, for example.

So in the case of KTTV, the viewer could still find its programming on Channel 11--even if the signal really is on Channel 43.

"If you've been Channel 9 for the last 50 years, there's some brand identity there," said Dane Ericksen, senior engineer at Hammett & Edison Inc., a Northern California broadcast engineering firm that is advising dozens of stations nationwide on the digital television conversion.

Competing at the low end

But migrating to the higher frequencies is a costly proposition. Broadcasting in the Ultra High Frequency (UHF) spectrum, which currently encompasses channels 14 through 69, uses as much as five times the electricity to reach the same area as the Very High Frequency (VHF) spectrum that runs from 2 to 13. The difference could run as high as $10,000 a month for stations.

Given the costs involved, Ericksen and other experts said they expect stations to cut deals before the FCC-imposed deadline for resolving interference issues. Most stations received their notices of impermissible interference in June, so the deadline would be next month.

Some stations might be willing to weaken their broadcast signals, conceding viewers on the periphery of their markets in exchange for being able to stay on their existing frequencies. Others might engage in a more complex process of bartering some channel placements for others, either in individual markets or even nationwide.

Competition is expected to be fiercest for frequencies at the low end of the VHF spectrum.

"There's a competitive impact if you have to change the channel slot," said Paul Gallant, an analyst specializing in digital television for the Stanford Washington Research Group. "There's also evidence that stations that provide the same programming at the lower end of the dial generally get higher ratings than those at the higher end of the dial."

The process of going digital has been fraught with delays. After resisting the 2007 deadline imposed by Congress, the broadcasting industry earlier this month agreed to go fully digital in 2009.

Starting in July 2007, all television sets with screens larger than 13 inches must be equipped for digital signals. Currently, more than four in five sets in homes are not compatible with the digital signals, although converter boxes are available for as little as $50.

Broadcasters already have spent an estimated $3 billion on new studios and transmitters for digital television.

The competition for frequencies is an inevitable step in a multi-year process that some say is the biggest change in broadcast television since the advent of color in the 1960s.

"You almost have to look at this as a checkerboard with the red squares being analog and the black squares being digital and everyone moving the pieces across the board," said David Donovan, president of the industry lobbying group Association for Maximum Service Television: "Right now we're in the middle of the game."