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Rohde Transmitter Boosts Efficiency at WCJB-TV

The Rohde & Schwarz THU9 solid-state transmitter GAINESVILLE, FLA.—WCJB-TV is owned by Diversified Communications and has been the ABC affiliate in this market since 1973. As part of our initial foray into digital broadcasting more than a decade ago, we opted for a solid-state DTV transmitter to take advantage of the technology’s reliability, elimination of high voltages and reduced maintenance requirements. Our power level—10 kW TPO—allowed us to take this approach and the benefits of solid-state technology were more than enough to justify the rather poor 17 percent operating efficiency the transmitter industry was able to offer then.


However, we found that as that first transmitter aged, its exciters became less and less reliable, and parts and service were increasingly more difficult to obtain. With these challenges in mind, we began planning our next upgrade. Increased performance was top of the list for any exciter upgrade, but long-term platform support was a close second. We also were thinking of adding new capabilities such as mobile DTV in the future, so the evaluation of possible systems included the flexibility and capacity to support our evolving requirements.

We had heard about Rohde & Schwarz doing exciter retrofits at other stations and asked them for a proposal for an exciter upgrade. In our discussions, the possibility of improving our electrical efficiency also came up. More specifically, we learned that the company’s THU9 UHF transmitter was able to provide greater than 30 percent efficiency, meaning that the installation of a THU9 would not only solve our exciter reliability problem, but would also cut our transmitter power bills in half.

While we were certainly intrigued by the potential for significant energy savings, our initial assumption was that such technology would have a price tag that would put the project far beyond our budget (even considering reduced electrical power expenses). Needless to say, we were pleasantly surprised when we learned that we could fit the entire transmitter replacement project into our budget. We would then be able to deploy a more reliable, efficient and well-supported system and eliminate the need to invest any more in our old, inefficient transmitter.


The transmitter was delivered on time and, with help from Rohde & Schwarz, the installation went smoothly. The liquid cooling system is so quiet, that when we first powered up the transmitter we thought something was wrong—we couldn’t hear anything. (Our old transmitter was air cooled and quite noisy.) We can now make phone calls from the transmitter room without having to shout and strain to hear.

Our THU9 has been on-air for several months, and while it’s nice to know that Rohde & Schwarz keeps a ready supply of spare parts at their service center in Maryland, we really haven’t had any need to tap this resource.

We were so pleased with the performance of our first Rohde & Schwarz transmitter that our company is now planning to replace the VHF transmitter at our Bangor, Maine station with a Rohde & Schwarz unit.

Steve Ingram is the chief engineer at Diversified Communication’s WCJB-TV. He may be contacted For additional information, contact Rohde & Schwarz 888-837- 8772 or