Perhaps no piece of DTV technology offers more variety than transmitters, which range from low-power VHF systems in the $50,000 range to high-power UHF systems that approach $1 million. And that's a good thing because today's broadcasters are approaching their different transmission challenges in a variety of ways.
To begin with, there are the digital and analog sides of the equation. With respect to digital TV, many broadcasters have been operating at less than full power since the FCC relaxed the power requirements in 2001. But that trend is slowly changing, and the FCC is expected to require large-market stations to go to full power beginning in mid 2005.
Analog may not be as hot a topic as DTV, but it is still where TV stations take in 100% of their revenues. And it looks like that won't change anytime soon, encouraging transmitter makers and buyers alike to keep selling and buying analog transmitters. For some stations, that means replacing very old analog transmitters with very new ones.
"If a 20-year-old transmitter is on its last legs, it's on its last legs," says Dale Mowry, Harris vice president of transmitters. "That's why you see an interest."
Others are looking ahead, buying new transmitters for their existing analog service because they plan to eventually return their station's channel assignment to its analog VHF allocation or they'll convert an analog UHF unit for high-power DTV use.
"I believe there's a big opportunity in analog and DTV for VHF," says Axcera Director of Marketing Rich Schwartz, who expects that broadcasters with VHF-UHF allocations will move to reclaim their analog VHF spots if possible.
No matter what the solution, however, one goal remains: installation of a transmitter that will reduce a station's power bill.
To that end, Acrodyne Industries (Ai) is bringing multi-stage depressed collector (MSDC) technology to high-powered analog UHF transmitters. According to President and Chairman Nat Ostroff, an MSDC can save money on both analog and digital signals. A 25% saving, he explains, might mean $75,000 a year in digital, $35,000 in analog.
Ostroff is putting his money where his mouth is. He also serves as vice president of new technology for the Sinclair Broadcast Group, which owns a stake in Ai. Sinclair has just installed three Ai Quantum depressed collector transmitters at its stations in Baltimore. A 240-kW unit at The WB affiliate WNUV will handle analog broadcasts for both WNUV and WBFF; one 60-kW unit each at WNUV and Fox affiliate WBFF will support DTV. "Those three transmitters will save a quarter-million dollars a year in power bills," Ostroff says. The 240-kW transmitter is replacing older klystron technology, he explains; the two digital transmitters are being switched to the more cost-efficient MSDC.
Two approaches to cooling transmitters involve use of oil-cooled tubes and water-cooled tubes, both of which are used with MSDC transmitters.
Ai's current MSDC products use water-cooled ESCIOT tubes from E2V Technologies and will also support Thales water-cooled tubes. Using water-cooled tubes allows the transmitters to be used for analog UHF applications. Ai does not support oil-cooled tubes.
Also entering the MSDC market is Harris Broadcast with the PowerCD Digital MSDC inductive-output-tube (IOT) transmitter. Vice President of Transmission Systems Dale Mowry says the company has been developing MSDC transmitters for some time but the technology has only recently been ready for prime time.
"The record is looking good on the ability of the IOT to produce power and efficient representation of the signal," he adds, noting that a range of frequencies and power levels has been tested.
In addition to MSDC tube technology, the new PowerCD includes an advanced network-monitoring and -control system. "We think the transmitter will become a network appliance," says Mowry, "bringing monitoring and control into the station."
Over the past eight months, some early DTV customers have returned to Harris for a second round of DTV transmitters. Some of the large groups, he says, are adding redundancy while others are moving to full power to replicate their analog coverage area.
Harris will also take an all-new solid-state NTSC transmitter to Las Vegas. The Atlas UHF, designed for operation in the 5- to 30-kW range, is aimed at analog replacement in the U.S. and overseas.
Axcera has seen a good deal of low-power DTV business ranging from low-power groups like Trinity Broadcasting to full-power customers looking for a lower-power DTV product. But that pattern has changed over the past year, says Schwartz. DTV sales have shifted to high- and medium-power units.
"We're at the point," he says, "where I believe most broadcasters are feeling they aren't going to be able to run low-power much longer."
Axcera offers a high-powered MSDC IOT digital transmitter, the Visionary DT, with either oil-cooled or water-cooled tubes. At NAB, it will also introduce a high-power solid-state VHF transmitter, the Innovator HX.
Thales Broadcast & Multimedia will be showing its MSDC-based DCX Paragon IOT UHF digital transmitter for the third year. The company already has 12 units in the field, says Joe Turbolski, director of marketing and sales operations.
He echoes Ostroff on power savings and adds that "we've also done things to the transmitter design to make it easier to maintain."
Although Thales showed the Paragon with an oil-cooled tube from L3 Electronics at the 2002 and 2003 NAB, it will also be offering a water-cooled ESCIOT tube from E2V this year; Thales will still make units with the oil-cooled tube.
"We went with an oil-cooled tube because initially that was what was on the market," say Turbolski. "But we have tried to design the cabinet to work with anybody."
Thales will also introduce a solid-state VHF NTSC transmitter, the Optimum-II, aimed at VHF broadcasters that are "limping along" with 20- to 30-year-old transmitters. The Optimum-II is easily upgradable to DTV operation, making it attractive to high-VHF stations.
Larcan will also introduce an entirely new VHF transmitter product at NAB. Steven Zakaib, vice president of sales and marketing, wouldn't give details, saying only that "it's a new technology and new design architecture."
Recently, Larcan has been selling a fair number of solid-state analog transmitters, in both the UHF and the VHF bands.
"A lot of customers still believe analog is their bread and butter. They want to buy a digital transmitter for the future," Zakaib says. Solid-state transmitters are ideal as a backup, he adds: "You can turn on a solid-state transmitter in five seconds."
Most recent solid-state customers are broadcasters hoping to return to their analog allocation, whether in the VHF or the UHF band. Zakaib is also busy handing out quotes to broadcasters looking to maximize their DTV power pending the FCC's expected ruling. Even a UHF station with a primary VHF DTV signal needs a quote for full-power UHF so they have something in the budget and can request the funding for it.
"That's a sign," he adds, "they're reading in the tea leaves that the FCC is getting serious about this [transition to digital]."