05.09.2003 12:00 PM
CEA tubes could prove cost-effective for DTV transmission

Public television station WDSE, in Duluth, Minn., lit up its digital transmitter for the first time at the end of April with a new Constant Efficiency Amplifier (CEA) tube that they think will reduce their electric bills by up to 60 percent. The cost saving is significant when you consider that many stations are reporting average power bills of $10,000-$15,000 per month to keep a full-power digital signal on-the-air with current inductive output tube (IOT) technology.



WDSE’s chief engineer Rex Greenwell (left) said the station is using CEA tubes inside a Thales Broadcast DCX Paragon MSDC IOT digital transmitter, at 730 kW ERP. That’s enough to adequately replicate their exiting NTSC service.

Rex Greenwell, director of engineering and operations for Duluth-Superior Area Educational TV (parent to WDSE), said that although the CEA tube is heretofore relatively untested in the “real world,” the initial tests have proved very promising. The station is using the tubes inside a Thales Broadcast DCX Paragon MSDC IOT digital transmitter, at 730 kW ERP. That’s enough to adequately replicate their exiting NTSC service.

WDSE is broadcasting a SD signal 24/7, and has no immediate plans for HDTV transmission. “There’s no doubt that the cost of ownership with the new digital transmitters makes this type of technology very attractive,” Greenwell said. “It could save us a substantial amount of money in operational costs. We’re looking at efficiencies of approximately 60 percent. With limited resources, I can’t ignore that.”

The new CEA tube technology is said to achieve twice the power efficiency of standard IOTs, according to L-3 Communications, makers of the new CEA tube.

By combining IOT and Multi-Stage Depressed Collector (MSDC) technology, the CEA reduces power consumption by about one-half compared with other methods. Correctable average power output of 30 kW has been demonstrated, L-3 said, matching the power available from conventional IOTs. The collector is oil-cooled using Poly Alpha Olefin oil, which allows operation at high average power.

Although Greenwell’s station is the first to use the CEA tube--or MSDC IOT, as some call it -- is not alone. Buzz Miklos, director of sales and marketing at L-3 Communications, said that with the cost of the DTV transition straining most stations’ budgets, saving money through power efficiency has become very attractive. Other stations set to go on-the-air with the digital transmission technology in the next month include KBIE-DT, in Sacramento, Calif.; KLRU-DT, in Austin Texas; WFSE-DT, in Hartford Conn.; and WNED-DT, in Buffalo, N.Y.



The new CEA tube technology is said to achieve twice the power efficiency of standard IOTs, according to L-3 Communications, makers of the new CEA tube.

L-3 does not directly sell the tubes to station, but instead markets the technology through transmitter manufacturers like Thales, Axcera, Harris Broadcast and Itelco.

Joe Turbolski, director of marketing at Thales Broadcast & Multimedia, said that the DCX Paragon transmitter utilizes the MSDC IOT to offer “unprecedented leaps in transmission efficiency and reliability.”

Miklos admitted that because the tube is so new, it requires a bit of custom tweaking at each location to get it to operate properly. “Because it’s a brand new product and engineers in the field do not have a lot of experience with it, we’re having to send our engineers on site to help get the transmitter up and running, but every station that has installed it is very satisfied,” he said.

He said that his company is being extra careful to make sure customers are happy. “It’s important for us to be successful with this technology right out of the box, because issues do arise in this business, through no fault of the new CEA tube,” he said. “There are unique issues with every transmitter we install, but thus far nothing that hasn’t been overcome quickly.”

Headquartered in New York City, L-3 Communications markets a variety of products to the broadcast industry, through its Wescam and Wolf Coach divisions. Another division, L-3 Satellite Networks, is a manufacturer of high-quality satellite communications products and systems for digital video broadcasting, Internet satellite service, traditional teleports, and Very Small Aperture Terminals (VSATs).

For more information visit www.L-3Com.com.

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