KCTS is first pubcaster to air FCC-standard DTV signal
Originally published in Current, Feb. 3, 1997
KCTS in Seattle became the first public TV station to broadcast digital TV in January 1997, using the nation's new transmission standard approved in December by the FCC. [Two more public TV stations installed transmitters for digital experiments in March 1997.]
Three commercial stations already had begun airing DTV test signals, the most recent being Seattle's ABC affiliate, KOMO, on Jan. 20, according to Cliff Anderson, KCTS director of engineering.
Within public TV, four other stations are planning to fire up experimental transmitters, as KCTS has done: WETA in Washington, D.C., Oregon Public Broadcasting in Portland, WMVS/WMVT in Milwaukee, and WGBH in Boston. The five public TV stations are members of the Digital Broadcasting Alliance, which promotes cooperation in their work. WETA expects to receive an antenna and a Harris transmitter this month and to begin DTV broadcasting in March, says Joe Widoff, senior v.p.
In its experiment, KCTS is now broadcasting random digital bits, but technicians hope to add a test pattern and eventually moving HDTV pictures, which PBS plans to distribute nationally. "Had we been able to transmit a picture, we wouldn't have been able to see it," Anderson adds. KCTS technicians could only look at the signal on a spectrum analyzer; they don't have a Grand Alliance receiver, and only a few prototypes exist.
But KCTS is trying to obtain receivers when they begin coming out of factories later this year, with hopes of staging public demonstrations, according to Steve Welch, director of high-definition productions at KCTS.
KCTS obtained permission for a one-year DTV experiment on Channel 18; borrowed a new silicon-carbide solid-state transmitter from the Harris Corp. and Westinghouse; and an antenna from Dielectric Corp.; and purchased a Harris modulator/exciter that will be usable when regular broadcasts begin. The low-power signal--500 watts peak power and 100-150 watts average power--favors the east side of Seattle, home of Microsoft and other interested high-tech companies.
OPB, WETA install gear for digital TV testing
Originally published in Current, March 31, 1997
Two more pubcasters joined the pioneers of digital television this month--Oregon Public Broadcasting in Portland and WETA-TV in the Washington, D.C., area.
OPB went on-air March 5 with a random-bit datastream using the FCC's new DTV standard, and WETA expected to follow late last week. Already operating were one public TV station, Seattle's KCTS, which signed on in January, and a handful of commercial TV stations. Pubcasters at WMVS in Milwaukee and WGBH in Boston plan to join the elite circle.
When the rare prototype DTV equipment becomes available after next week's National Association of Broadcasters conference in Las Vegas, WETA hopes to begin demonstrating DTV broadcasts of high-definition tapes.
The stations are operating under experimental licenses, on temporary channels, and most are using low-power, temporary receivers from the Harris Corp.
WETA, however, purchased a Harris Sigma CD digital transmitter with peak power of 70 kilowatts, with plans to use it during the multiyear DTV transition period, says B Morse, a former NPR executive who is helping the station go digital. With the antenna side-mounted on WETA-FM's tower, the 70kw transmitter will be able to cover the TV station's city-grade contour, station engineers believe. During the experimental period, however, the transmitter's power will be limited to 10kw.
Under terms of a planning grant from the Public Telecommunications Facilities Program, the WETA experiment will be guided by an advisory committee of engineers from 10 other public TV stations. One of the first tasks, the committee has decided, will be to devise technical specs for multiplexed multiple-service broadcasting in a single DTV channel, according to Morse. The bitstream could be divided fluidly into two big and one little channels on some occasions and four medium-sized ones at other times.
OPB emphasized this capacity in its press release. "Digital television is a tool we can use to achieve our mission--to be Oregon's most accessible learning resource," said OPB President Maynard Orme in the release. "It gives us the flexibility to broadcast preschool programming, classroom videos, adult learning and public affairs programming all at the same time."
He especially wants to develop an entirely pledge-free channel for paid-up station members only.
Orme is eager to develop unforeseen new services using DTV. "What we're doing at first is using a new medium to broadcast the old medium," he told Current. "What we are trying to learn is how to develop that interactive component. The new device is a hybrid multimedia interface, it's not a television set."
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