If you build it, they will come.
In fact, sometimes you just merely need to TALK about building it, and they will come.
Congratulations to Chapter 37 of the Society of Broadcast Engineers for bringing together more than 50 attendees to learn about the benefits and drawbacks of shared antenna systems.
“AntennaFest 2025: Shared Signals” was a first-time event held on Oct. 7 at the headquarters of WETA in Arlington, Va., just outside of Washington, D.C. Its entire focus was on systems that allow multiple broadcasters on multiple frequencies to use a single transmission system and antenna.
William Harrison is chief engineer of WETA and chapter chair of SBE37.
“The number of broadcast towers keeps going down as corporations realize that the land beneath them is worth more than the tower space is,” William told me.
“So they get taken down and typically aren’t rebuilt. This forces broadcasters to try to relocate to other towers, which may not have space for additional antennas. Sharing one becomes desirable for a number of reasons.”
The idea of a gathering on such a specialized topic came about as the chapter board discussed meeting ideas. They realized that the D.C. market has shared antenna systems from three different manufacturers. Those systems differ in the technologies employed and specific requirements such as directionality and gain.
“We thought it might be interesting to discuss why certain manufacturers made one choice over another for a given project,” William explained.
“It quickly became apparent that such a discussion would require background information from each manufacturer, and it wasn’t going to fit into our typical monthly meeting evening time allotment.”
That, combined with advances in the technology of combiners, antennas and system monitoring, suggested a half-day special gathering.
They asked each presenter if their companies would be willing to help with costs on an equal basis. All agreed. William wanted the event to be unbiased toward any one sponsor. Chapter 37 contributed an equal share, because such events help advance the education of members.
The chapter invited major U.S. antenna manufacturers. It also invited a tower management company, because many stations lease tower space or access to a shared system. It asked a transmitter manufacturer to talk about basic of RF in the context of combined systems. And it invited an RF consultant to provide perspectives on things engineers and managers may not think of before calling a manufacturer to get pricing.
Thus the event included presentations by Ben Brinitzer of American Tower; Gary Cavell of Cavell Mertz at Capitol Airspace Group; Cory Edwards of Dielectric; Nick Paulin, P.E., of Electronics Research Inc.; Jeff Welton of Nautel; and Steve Wilde of American Amplifier Technologies, parent of Shively Labs.
“For me personally, I really enjoyed seeing how far the industry has come through the use of technology,” William said.
“I’m amazed that we now have the ability to monitor transmission systems in real time, constantly, while they are running at full power, without disruption to broadcaster. And in the design stage, being able to use complicated computer modeling systems to not only predict coverage but then iterate through thousands of possible configurations in order to determine the optimal layout of a system is incredible — something simply not possible just a few years ago. The use of HFSS and AI have become much more prominent.”
He felt it was important to discuss questions that engineers may not have thought through before deciding to proceed with a a combined system.
“Asking not only ‘Can it be done?’ but also ‘Should it be done?’ is only the beginning,” he said.
“Does it make sense to move to a combined site? Do we lose population coverage based on the pattern change? What would this gain us? Would we be allowed to move from the point of view of the FCC? Can the tower handle the additional load of a shared antenna or larger feed line? Would the move require FAA coordination based on the frequencies involved?”
He said that there’s clearly no single “right way” to build a combined system.
“Every situation is different, and the requirements dictate the approaches taken. And you don’t know what you don’t know — I’ve met folks who didn’t know combining was even possible, to those who believed that you can only combine two frequencies, to folks who didn’t think you can combine omni with directional coverage.
“Whether you’re new to the business, or an IT guy being pulled into engineering, or a seasoned RF engineer, there’s always something new to learn.”
Video of the entire event will be posted soon on SBE37’s YouTube channel. And you can access all the presentation materials right now at the chapter’s website.
I like sharing initiatives like this with you.
Recall me telling you about how the engineering team at Cumulus station WJR(AM) in Detroit hosted members of the region’s emergency alerting community. I thought that was an excellent example of how broadcasters can interact with local authorities.
Chapter 37’s event is a much different animal, yet it too is proof that local engineering communities don’t need to rely on national associations and conferences to organize useful events. Putting together something like this does require a lot of time from a committed organizer, so go in with your eyes open. But if you plan it well, folks will come. And if you ask nicely enough, experts from the manufacturing and consulting communities might just come to you.
Congrats to Chapter 37 for a successful and well-conceived event. And my thanks to our friend Jim Peck of SCMS who provided the photos.
[Related, from 2020: “New Master Antenna System Serves D.C.”]
