07.18.2002 05:26 PM
A TRIBUTE TO PBS
When It Comes To Digital, PBS Has Won The Race
The name "PBS" conjures up images of quality children's programming, astronomy specials, marathon fundraisers, and prize-winning documentaries. When you think of PBS, a show that comes to mind is certainly not Survivor or American Idol. There's no doubt about it÷public television doesn't look, act, or even sound like what's on the other over-the-air channels.

That's because, at the heart of public broadcasting is a mission vastly different from that of commercial broadcasters. PBS's chief aim is to offer quality programming, educational features, and other services to the local viewership.

Commercial broadcasters entertain and inform their viewers, but ultimately are driven by the need to run profitable operations.

When PBS and its affiliates consider new technologies, they look at how the technology can expand and make more efficient their services. Efficiency, of course, often means keeping a tight reign on operating costs. So, when PBS jumps ahead of its commercial broadcast cousins in adopting new technologies, it's sometimes driven by the need to cut its operating budget. Being mostly parked in the UHF spectrum, there's always a need to find ways to lower the power bill of those energy-hungry UHF transmitters.

A Pie In The Ear

Being a pioneer isn't easy. It takes guts to put your career and your station's future on the line. Once, when I labeled one of the industry's top engineers a "pioneer," he quipped, "Sometimes when you're a pioneer, you take the pie in the ear!"

At the 1987 NAB convention, Nat Ostroff, who was then president of Comark (which is now Thales Broadcast & Multimedia), confided to me that he was about to embark on helping launch a new, not-yet-field-tested UHF high power tube that would shatter the then current efficiency record. It would be called the Klystrode. Behind the scenes was a team of Eimac engineers who believed the Klystrode design would work. Eimac was in competition with its parent company (Varian) to produce the first new high efficiency, high power UHF tube. Varian called its tube the MSDC.

At that same convention, I sat with George Badger, Merrald Schrader, and Don Preist from Eimac and discussed the Klystrode theory over lunch. I couldn't understand it until Preist drew a diagram on a napkin and handed it to me. For history's sake, I should have kept that napkin!

While the industry's leaders were backing the MSDC, Ostroff was certain the Klystrode would work. And that's when Georgia Public Broadcasting (GPB) entered the picture.

GPB Director of Engineering Al Korn believed in the Klystrode and convinced his boss, Frank Bugg, to have faith in it as well. So an agreement was struck between GPB and Ostroff to turn on the first Klystrode-equipped (IOT) transmitter in the world.

Meanwhile, I was busy writing articles about the promise of the Klystrode, when my boss called me in to challenge my backing of the new tube. After explaining the potential role we could play in broadcast history, he reluctantly agreed to let me go forward.

Early in 1988, Al Korn turned on the first Klystrode-equipped transmitter in GPB's statewide network. A piece in Television Broadcast at the time quotes him as saying, "We are making footprints in the sand where no one has been before."

And that series of events led to new designs, known generally as IOT tubes. Today there are many high efficiency IOT-type devices coming to market, but the IOT got its start because the engineers at Eimac, Nat Ostroff at Comark, Al Korn and Frank Bugg at GPB, and Television Broadcast magazine believed in it. The Klystrode-equipped transmitter won an Emmy in 1991.

Fast Forward

DTV is the current driving force across the entire broadcast industry. While commercial broadcasters grope for new business models, PBS affiliates are ahead of the FCC-mandated digital turn-on dates because DTV offers endless opportunities to extend their services.

The University of North Carolina Public Television Network (UNC-TV) recently signed a contract with Harris Broadcast for transmitters for its 11-station network. The deal calls for Harris to deliver solid state DiamondCD UHF and Sigma CD-II UHF transmitters to complete the transition to DTV. UNC-TV also awarded Harris a contract for phase one of a $8.2 million master control integration project for the entire UNC network. UNC-TV counts among its varied offerings descriptive video services for the blind, which include brief audio scene-by-scene descriptions of programs.

One state south, South Carolina ETV (SCETV) jumped the gun on DTV in March 2000 when it turned on a DTV signal at WLRK-Digital in Columbia. But SCETV isn't resting on its DTV laurels. It is in the process of building Newsplex, an experimental training facility at the University of South Carolina. Newsplex is probably best described as a micro-newsroom. It will feature approximately 10 workstations, from which journalists will sample different productivity solutions for a converged media workplace.

On With The Show

For the last four years, KLVX-TV in Las Vegas has treated NAB attendees to DTV signal demonstrations at a number of booths. KLVX is unique among PBS affiliates in that the station is owned by the local school district (Las Vegas). According to General Manager Tom Axtell, KLVX has been involved in a number of high profile demonstration projects, but, "Our mission is to serve the public and the school district, with the emphasis on the school district's needs. Since we are owned by and are so closely tied to the school district, that makes our station somewhat unique.

"We focus on delivering services to the schools. In fact, overall it's an unbelievable array of services, which even include helping schools design their security systems."

Axtell says the transition to DTV was aided by the fact that it uses channels 10 and 11, meaning it could repurpose its old antenna by using a combiner and multiplexing the signals. "Of course," he said, "the fact that the Thales is liquid-cooled is great because we're in a desert climate."

Getting Your Feet Wet

There's also the thinking at some PBS member stations that testing the waters isn't a bad idea. At KNME-TV, University of New Mexico (Albuquerque), Director of Engineering and Operations Jim Gale decided to start the station's DTV operations at very low power.

With Larcan's cooperation, Gale opted for firing up a modified Larcan MX-100U that's delivering 30 W RMS with an ERP of just 384 W. He is using an Andrew AL-8 antenna and feeding it with an Andrew Heliax. "Getting on the air with low power makes it easier to spot reception problems," said Gale.

Within two hours after turning on KNME's DTV signal, Gale began getting calls from area viewers. And that started what has become a DTV user group that meets monthly at the station.

Plans are to move to higher power, but how high that power is may depend on a Federal Grant requirement that stipulates running full power. At press time, Gale reported that viewers are seeing good pictures from about 40 miles away.

KNPB-TV in Reno, NV, felt that its allocated power of 50 kW was excessive. Two years ago it also started out using low power to access the power it actually needed for its license coverage.

At KERA-TV in Dallas, TX, the station was concerned not so much about the distance covered as much as about interference to local two-way business radio systems. It teamed with Axcera to use a unique combination of computer-controlled solid state amplifiers run through a custom digital filter. KERA-TV turned on its DTV transmitter on December 4, 2000, running an Axcera Innovator transmitter at 3 kW. The coverage was about 50 miles. Adding a new antenna, KERA-DT bumped its ERP to 20 kW on October 6, 2001.

Fade To Success

The stations covered in this article are just a few examples of some of the innovative projects being undertaken by PBS affiliates throughout the country. Every PBS station prioritizes its programming and services to meet the special and unique needs of its diverse audience.

Datacasting, multicasting, streaming video, and distance learning are technology icebergs being melted eagerly by PBS affiliates, but each station and statewide network insists that technology only makes sense when it helps expand its services or cuts operating costs. In that way, all PBS affiliates are winners. n Editor's Note: Other transmitter manufacturers have routinely been supplying their rigs to PBS affiliates. These companies include Emcee, Itelco, and Rohde & Schwarz (available in the U.S. exclusively through Ai). Ron Merrell is executive editor of DigitalTV.

>For More·

Ai
www.acrodyne.com

CPI/Eimac
www.eimac.com

Emcee Broadcast Products
www.emceebrd.com

Harris Broadcast
www.harris.com

Itelco
www.itelco-usa.com

Larcan
www.larcan.com

PBS
www.pbs.org

Rohde & Schwarz
www.rohde-schwarz.com

Thales Broadcast & Multimedia
www.thales-bm.com


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