07.18.2002 05:59 PM
A TRIBUTE TO PBS
PBS's Diverse Digital World
Approximately 75 of the roughly 349 PBS stations in the U.S. are transmitting a digital signal, covering around 55 percent of households in the country. But "digital" is a complex term, meaning anything from standard definition transmission of television signals to nonlinear editing. Once a station is about to launch its digital signal, a decision has to be made as to what percentage of the programming should be high versus standard definition. Most of the PBS affiliates that have gone digital are implementing some form of multicasting, such as WSRE-TV in Pensacola, FL. According to the station's Director of Engineering, Roland Philips, it runs two standard definition channels of programming during the day and high definition programming at night. It does not originate its own programming, but picks it up from the national PBS feed.
Meanwhile, Oregon Public Broadcasting has chosen to run mostly high definition programming. "We have been on the air in high definition for almost two years," said Don Mckay, director of Engineering at KOPB-TV in Portland. "We started with a combination of standard definition during the day and high definition in the evening and found that it was very difficult to switch from one mode to the other, because it would crash receivers. The high definition programming was downconverted from PBS en masse. We got complaints from people saying that our standard definition didn't look very good because our analog signal is still a composite mode and once you digitize that it doesn't look very good. Then we went to one high definition/one standard definition all the time to get away from the crashing receiver problem. We did that for six or eight months." In the end, Mckay decided to go with high definition: "Our present mode is everything in high definition," he said.
Bill Burroughs, director of Engineering at KCET-TV in Hollywood, said the station went on the air with high definition full time in June of 2000. "A big part of our programming day is the PBS high definition loop [the national feed for high definition programming supplied by PBS]. We have a couple of programs a week that we originate."
Leon Messenie, engineering supervisor at KPBS-TV in San Diego, said his station is originating its own HD programming. "We are doing no pass through," he said. "We get programs from producers and organizations on tape, either HDTV5 Panasonic tape or HDCam Sony tape and ingest it into our HD profile server system and from there we play out programs 20 hours a day. There are a lot of repeats because there's not that much content out there. It's getting better every day, but a program may repeat 10, 15 times in a week."
KCTS-TV, in Seattle, WA, runs a pair of channels out of its digital station. Tim Schall, the station's transmitter supervisor, said "We've got an HD stream that is HD full time and we have an upconverted analog stream that is standard definition all the time. We do occasionally upconvert some 16:9 standard definition material and run it on the HD station÷maybe one or two of those a month. The HD station is HD full time and the SD station is SD full time."