THROUGHOUT THE 1980S AND EARLY '90s, American television engineers dreamed of the day a high-resolution television system could be introduced in the U.S. Paying little attention to what such a system might cost (perhaps $100 billion, most of it headed for the Far East) or to its social and political implications, these engineers plunged forward until December 1996, when the FCC approved a digital transmission system known as DTV. Once that part of their dream had been realized, however, the engineers were faced with an enormous task: how to take digital broadcasting beyond the laboratory and into the 24-hour, everyday world of commercial and public television. Perhaps more important, every station's financial officer is now faced with the challenge of paying for it, which means rallying advertisers around a new broadcasting system that reaches only a minuscule segment of the population.
The financial people remain on hold, but the engineers and technicians have been moving forward. DTV is here, today, and it works — in demonstration, at least. In January 1999, thousands of consumer-electronics insiders and opinion makers were treated to a massive demonstration of true over-the-air, multichannel DTV broadcasting at the Consumer Electronics Show (CES) in Las Vegas. Dozens of sets from almost every manufacturer were displaying perfect, high-definition pictures. Yet, something was askew in Sin City. TV Technology, an engineering trade magazine, would later report that a number of “tweaks” had been required to make this seamless demonstration possible. Specifically, three separate antennas (one for each DTV channel) were employed on a very tall tower, and an elaborate “cable TV”type system was required to decode, resynchronize and then re-encode the three stations' signals before sending them, by cable, to the sets on the show floor.
FORTUNATELY, ALL LOS ANGELES broadcast stations, including their DTV transmitters, are located at one point: Mt. Wilson in the San Gabriels. Unlike the real residents of Las Vegas and other parts of the country, L.A. viewers will not need to rotate their antennas to pick up different DTV stations. The height, size and type of antenna, however, is still an issue. Rabbit ears won't work; only in Europe is a robust, medium-definition digital system delivering perfect pictures to viewers with simple set-top antennas.
But most Los Angeles viewers get their television by cable or satellite, and here's where the picture gets hazy. DTV signals can be received, decoded and recoded for transmission over cable, just as they were in Vegas, but there's a problem: A single DTV channel can take as much “bandwidth” on a cable system as six to 10 compressed channels of regular television, and there's very little mandate at this time for cable companies to carry DTV channels. Cable operators — faced with a choice of carrying five Los Angeles DTV channels for a handful of viewers, or 50 new networks and pay-per-view movie channels to all their viewers — have chosen, and will likely continue to choose, to stick with “regular” television as long as possible. Mini-dish satellite operators, including DirecTV and an HDTV specialty system called Unity Motion, will (at some point) offer high-definition movie programming, such as the new HBO-HD channel, but have no plans to provide ABC/NBC/CBS/ PBS-type programming in DTV. Mini-dish owners who've already set up an outside antenna to receive local stations are probably in the best position to receive DTV broadcasts.
But even with a large antenna, DTV signals don't reach everywhere that conventional TV does. Digital broadcasting follows what's known as the “cliff effect” — reception is either perfect, or drops off to zero. There's no such thing as weak but watchable reception with digital. Some or all of the viewers in “fringe” areas, including viewers right smack in the middle of the city who have bad ghosts or interference, may not be able to get DTV. In fact, even the FCC's conservative estimates show that up to 20 percent of each station's current audience probably won't be able to receive DTV signals. (They hope to improve this situation by increasing broadcast power, but only after all analog stations, which could otherwise receive interference from DTV, are shut off.)
Further, Canadians and Mexicans along the border currently enjoy American television, and their viewership is calculated in the bottom line of advertising rates at those stations. (Many U.S. stations on the southern border even carry advertising for Mexican businesses.) As neither country is expected to adopt the U.S. DTV standard, millions of viewers in those countries will lose American programming if the transition to digital is ever completed. And due to conflicts with new digital-channel assignments in this country, up to 1,000 low-powered TV stations, which mostly serve minority or distant markets, may have to go off the air.
Next week: “Los Angeles: Living With DTV.”