CHARLOTTE, N.C.—While the spectrum repack drives a large percentage of transmitter purchases in the USA, sometimes a TV station simply needs an upgrade. This was the case here at WBTV, where we quite literally owned Serial Number One from an IOT transmitter line that long ago ceased production.
Even without a channel change, it was clear that we needed a new transmitter but while the manufacturer remains in business, they no longer support that product line. We discovered that a tube could be built, with a six-to-eight-month lead time at costs approaching $100,000. Then there is the consideration of transmitter maintenance and efficiency—neither particular strong suits of this technology.
These factors led us to select a GatesAir Maxiva ULXTE solid-state liquid-cooled transmitter. The ULXTE is already paying dividends thanks to its remarkable efficiency across the “three Rs”: Receivability, Reliability and Real Cost Savings.
GAINS IN RECEIVABILITY
Raycom Media, our parent company, is a longtime GatesAir customer, and our experience with a backup Maxiva air-cooled transmitter factored strongly in our decision. Noting the efficiencies that this low-power transmitter delivers, we felt confident that a high-power, liquid-cooled version would outperform our four-IOT system in several capacities.
The benefits were immediate. While our transmitter facility is atypically large, footprint is always a concern. The fourcabinet ULXTE-120 fit cleanly into a space that once housed a massive RCA analog transmitter. We removed some leftover ventilation from a forced air-cooled system and slid the much more compact ULXTE into position with room to spare.
We also had bigger challenges to address. From a receivability standpoint, the ULXTE integrates GatesAir’s latest-generation exciter, the Maxiva XTE. Its performance has been nothing short of remarkable, and we were achieving shoulders and modulation error ratios above 40 right out of the gate.
These are incredible gains in receivability compared to our previous numbers, which were barely within the FCC requirements. We have routinely received phone calls from viewers that previously could not receive our programming. From a futureproof perspective, the XTE also prepares us for ATSC 3.0 with a simple software adjustment.
MODULARITY AND REDUNDANCY
The ULXTE’s reliability comes chiefly from its design. Its modularity and redundancy allows for continued operation near full capacity if a module is replaced. For example, losing a tube in our old transmitter resulted in a 25 percent power drop; losing an amplifier in the ULXTE results in a less than 1 percent reduction. Since all modules are palletized, it’s like working on any rack-mounted component: Slide it out, and slide in the replacement while remaining on the air. The challenges of keeping the systems phased and balanced are also in the past, as the solid-state design eliminates all tuning requirements.
Real cost savings is perhaps the most stunning development, as we have seen a 35 percent drop in our power bills. The math is clear: We have approximately doubled our transmitter efficiency, rising from 22-23 percent to 45.5. Where we once saw power bills in the $20,000 range per month, our first two ULXTE-influenced bills have landed at about $12,000.
We attribute much of this cost reduction to the highly efficient solid-state amplifiers, as we no longer need the costly high-voltage power supplies that typically accompany a tube, combined with a superior redesign of the heat exchanger. These are now horizontally-mounted units with frequency drive motors that are also quiet as a mouse. We can hold a conversation nearby, and they are easy to clean—two achievements that eluded us with the older heat exchangers.
As we look forward to ATSC 3.0, we are also enthused that the transmitter—currently powered at 67kw TPO—has plenty of headroom for additional services and design efficiencies. For the latter, we are considering a transition to a vertical pole in our antenna, which will further improve our broadcast parameters and receivability.
Mike Gurthie is regional director of Technology for Raycom Media and can be reached atmgurthie@wbtv.com.
For more information on GatesAir, please visitwww.gatesair.comor contact Keith Adams at 513-459-3447.
