It was a near miss last week for several radio stations as a fire in southern Colorado burned out of control.

The Aspen Acres wildfire came within several hundred feet of the Camp Jackson tower that contains critical emergency and commercial radio equipment, according to reports

The fire near Rye, Colo., has consumed nearly 100,000 acres of the San Isabel National Forest in the Wet Mountains. It also burned hundreds of homes across Pueblo County. As of Monday afternoon it was about 36% contained, according to news reports.

Semi-retired independent broadcast engineer Michael Baldauf, a Radio World contributor who helps maintain the broadcast site, told Radio World the fire came within a tenth of a mile of the mountaintop facility.

Camp Jackson is situated at an elevation of about 8,600 feet. The tower hosts broadcast antennas for KTPL(FM), WAY-FM’s KRWA(FM) and K-Love’s KWRY(FM) and KRNX(FM), all of which air Christian programming.

Baldauf said the stations have been off the air since power was cut to the tower site around July 1, shortly after the Aspen Acres fire started.

The site has achieved some prominence during the Aspen Acres fire, serving as a critical vantage point and infrastructure anchor for containment operations.

Baldauf himself lives about 10 minutes away but he was evacuated from his home two weeks ago.

He says the fire has burned through the foothills and is burning across the mountain face. As of Monday his home and Camp Jackson appeared to be safe barring a change in wind direction.

“The Sheriff’s Department escorted me up there last week. It all looks fine, but everything had a layer of pink dust on it from fire retardant. It was a very close call,” Baldauf told us.

“I turned off all the circuit breakers in the building so when power is eventually restored, the transmitters won’t automatically start back up. That way I can make sure they are ready to go.”

The four radio stations remain off air, Baldauf said, but the site is approximately 60 miles southwest of Colorado Springs, which has FM signals carrying Christian programming that can serve the Rye area.

He serves as a contract engineer for several of the stations. In the winter, he snowshoes into the site to perform maintenance duties.

“I’m the eyes and ears on the ground here. WAY-FM and K-Love have broadcast engineers in Colorado Springs, but this is so remote that it’s hard to get to.”

Camp Jackson was built in the early 1980s. There is no TV on the tower, Baldauf said, but there are several government agency repeaters.

Baldauf says it’s possible that Camp Jackson received protection from firefights because it had been used by the YMCA as a summer camp for underprivileged youth for about 50 years. The site has a medium-size lodge and some additional outbuildings.

“The fire service is looking to protect property and lives, so having the YMCA camp buildings there likely increased their attention to the area,” he said.

The Colorado Sun reported on Monday that the fire could burn for months.

[This article originally appeared in our sister publication Radio World. Their coverage of the industry is available here.]

You can see it from almost anywhere in the City by the Bay. No other landmark can make that claim — not the Golden Gate Bridge, nor any of the city’s skyscrapers. Including the ground, the tower has six levels, with hundreds of antennas.

Sutro Tower has stood for 52 years in San Francisco. To many residents, it’s now a sign welcoming them home.

“I think there are more Sutro Tower tattoos out there than Golden Gate Bridge tattoos,” Peter Hartlaub said on the Total SF podcast, produced by the San Francisco Chronicle, in an episode commemorating the tower’s 50th anniversary in 2023.

Co-host Heather Knight remarked that the tower can appear differently, viewing it for instance from the city’s botanical garden or from across the bay.

“It’s like a living thing,” she said.

The tower has come a long way to become a Bay Area icon. To know its story requires a visit to a moment in time when TV broadcasting was still novel.

Where to Place a TV Tower
In the late 1940s, television was on the bleeding edge. Engineer Bill Ruck recalls Ken Nielsen, his mentor, furnishing the John O’Connell School of Broadcast with an RCA TV package with cameras and control units. The inner-city school operated in San Francisco’s Mission District, part of the city’s unified school district. They used KALW(FM), the first FM educational station built in the country, for training.

A 1953 article from the Radio, TV and Recording Technician-Engineer described engineers and station supervisors, many of whom were former O’Connell students, assisting in organization, advice and hiring trainees. Nielsen was an instructor in the program. Ruck said that gaining any kind of knowledge was integral.

In San Francisco, determining the best place to broadcast TV stations from was a question that didn’t have an easy answer in the days before Longley-Rice-based studies, for example, were available.

“It was all kind of trial and error,” Ruck said.

By 1960, the five primary Bay Area TV stations were fielding complaints of poor reception, which required viewers to reposition their rabbit ears to get a clear picture. There were two separate sites. Channel 7, KGO(TV), had its tower at the site of the mansion, La Avanzada, the one-time home of Adolph Sutro, a San Francisco mayor in the 1890s.

ABC planned to reconfigure the mansion into a broadcast facility for KGO, its new local TV station. By 1949, KGO began transmitting from a 580-foot broadcast tower adjacent to the mansion. KPIX Channel 5 would join KGO there.

The San Francisco Chronicle’s KRON(TV), Channel 4, went on the air in 1949 from a tower on Mount San Bruno. The Chronicle was owned by the Thieriot family. Another prominent family in the city — friendly with the Thieriots — was the Crocker family, which owned Mount San Bruno. When the Chronicle wanted to put on a TV station, it was perfectly logical for them to go to the Crockers and buy property, Ruck said.

“All part of ‘old San Francisco money,’” Ruck remarked.

KQED(TV), Channel 9, joined them in San Bruno in 1954, and Channel 2 KTVU(TV), which signed on in 1958, did the same. KGO would propose a tall tower at Mount Sutro, while KRON proposed a tall tower on San Bruno. “Lots of consulting engineers made piles of money studying the two tall towers,” Ruck said. The two sites resulted in about the same coverage projections with the FCC, so the process stalled. Ultimately, a tall tower on San Bruno was blocked by the FAA, as it was much too close to San Francisco International Airport, about two miles to the southeast.

“That’s why Sutro Tower was built,” Ruck said.

In 1968, four TV stations — KRON, KGO, KPIX and KTVU — came together to form Sutro Tower Inc. Initial designs envisioned a 1,200-foot tower that had a restaurant and observation deck. Opposition ensued. Ultimately, a 977-foot height was settled upon. Construction began in 1971 and it was completed a year later. Antennas were mounted in 1973, and on July 4, the first broadcast from Sutro took place.

Ruck is the best living Sutro historian. He started working for 104.5 KFOG(FM) in 1978, which transmitted atop Sutro — today it is the FM side of sports-talk KNBR. Sutro’s manager at the time was Harry Jacobs, who dated back to working with KGO at the mansion. Ruck has been part of the San Francisco broadcast engineering scene ever since.

“The more I look into it, the more I'm fascinated with the pioneers that did it when it had never been done before,” he said.

After Jacobs retired, Don Lincoln took over. Ruck had access to a file drawer of Sutro history during that time. He remembers a “foot of paper” of reports. Their plans, Ruck recalled, only considered San Francisco, San Mateo and Alameda Counties. At the time, there were only ranches and almond groves in Contra Costa County and Santa Clara County.

“Nobody lived there,” Ruck said of their logic.

Today offers a much different story. In fact, Ruck said that if such a tower were being planned now, he’d put it in the East Bay, such as the site of 94.1 KPFA(FM)’s transmitter in the Berkeley Hills.

Navigating Public Perception
Early public relations for the tower — and the surrounding Twin Peaks, Forest Knolls and Midtown Terrace neighborhoods — was, at best, a struggle. Ruck recalls that in the early 1980s two more area TV stations wanted to move to Sutro. Its transmitter building did not have the space for more occupants. Management drafted a design to allot more space, which required a permit and public notice, leading to a lot of pushback. There are homes as close as 300 feet from the tower. Some neighbors refer to it as “an industrial complex.”

“San Francisco invented the concept of NIMBY,” Ruck joked.

Lincoln wanted to engage the neighborhood. He set up a public meeting where the benefits of the tower were highlighted. Ruck remembers being in attendance. Afterward, a neighbor across from where Ruck’s parents lived scolded him for being involved with Sutro Tower. “It was a PR nightmare,” Ruck recalled.

As an engineer, managing the mindset of an average person’s perception of a large tower in their backyard wasn’t necessarily part of Lincoln’s thought process. Ruck remembered suggesting to him that someone be hired specifically to manage neighborhood outreach. Ever since, Sutro has had someone in such a capacity.

How did Sutro become the regional symbol that it is today?

Cody Hmelar, former chief engineer for Salem Media and an instructor at the University of Pittsburgh, grew up in the Bay Area. He said feelings about the tower became warmer by the early 2010s, as what he described as “contemporary hipsterism” rose.

It was simultaneous to the growth in popularity of “Karl the Fog,” a personification for the city’s trademark low-cloud layer.

Its Clarendon Avenue location, he said, sets it apart from other Bay Area towers, prompting its use in local art, tattoo designs and even on the San Francisco City Football Club's uniform badge.

While its East Bay penetration may suffer to an extent, as Hmelar noted, Sutro’s inner-city location makes it a prime site for digital TV transmission — especially since the principal satellite and cable headends are in Petaluma, about 33 miles north of downtown San Francisco, and rely on a strong, centralized transmission source.

Managing Sutro Today
Lincoln would retire, succeeded as Sutro’s general manager by Gene Zastrow and Eric Dausman. Dausman in turn announced he was retiring in 2018.

Raul Velez, 56, recalls seeing Sutro Tower out of his bedroom window a few years after it was completed. “I didn’t know it at the time, but it was my source of [TV] cartoons, so it was really important to me,” he said. Velez received encouragement, including from Sutro’s primary RF consultant, Peter Eckmann, to apply for the opening following Dausman’s announcement. Now he guides outreach efforts.

“When I talk to folks and say ‘I work for Sutro Tower,’ they’re like, what?”

Velez has been involved in Bay Area radio engineering since 1989. He was chief engineer for Univision’s San Francisco stations from 2002 to 2016. More recently, Velez was Bonneville’s director of engineering for 96.5 KOIT(FM), 98.5 KUFX(FM), 99.7 KMVQ(FM) and 102.9 KBLX(FM) from 2017–2019, when he applied for the Sutro job.

From a distance, Velez remarked, Sutro looks static. But there’s work going on nearly every day. He works from an office in the reinforced concrete transmission building at the base, which also houses signal handling and transmission equipment. Sutro Tower operates with a dedicated team of five employees handling administrative, power and building maintenance, supported by contract security and external contractors like Full Wave Tower & Broadcast for specialized tasks.

Each entity, which could be TV, FM or two-way, has its own staff or team that is responsible for their infrastructure. “When I have 11 different TV stations with their own perspectives on the business, I have to manage and coordinate the individual philosophies,” Velez said.

TV stations KGO, KPIX, KRON, KTVU, KQED, KRCB, KPYX, KPJK, KCNS, KDTS and KFSF all transmit their signals from Sutro, representing ABC, CBS, FOX, PBS, CW and TelevisaUnivision.

Hmelar pointed out that in the Bay Area, over-the-air TV is particularly important, as there are several foreign-language and minority-owned media networks that make use of digital TV subchannels as their primary communication method. He noted the city’s language-access ordinances.

“It makes being able to broadcast in multiple languages essential,” he said.

On FM, 96.5 KOIT, 98.9 KSOL, 104.5 KNBR and translator 93.7 K229DD, which relays Chinese-language 1400 KVOT(AM), all call Sutro home. Two 102.5 LPFM stations maintain a timeshare from Sutro: KXSF(LP), operated by San Francisco Community Radio, and KSFP(LP), the San Francisco Free Press.

Seven amateur radio groups maintain facilities on Sutro, including the San Francisco Radio Club (W6PW). “We treat them like everyone else,” Velez said.

If someone calls and asks for a check on their suite to make sure a certain green light is on, for example, Sutro’s staff can save them a trip. Or maybe it’s to dispatch a telco company or assist an HVAC vendor. “Really, our job is to make sure the tower is still there every day,” he said.

Making the tower a “living thing” involves plenty of other hands-on endeavors the Sutro team has spearheaded. That includes a 360-degree, rotatable, movable, zoomable panorama of the tower, available at explore.sutrotower.com. Velez said the feature consists of 1,300-gigapixel images placed together, produced by the Portland, Ore.-based Panogs. A 13-minute documentary produced by Stimulant and a team led by Darren David explores the origins of the tower, from the history of the Sutro family to the opposition residents provided before it was erected.

Sutro also keeps up good relations with nearby Glen Park Elementary, where third-grade teacher Sheila Tenney has students draw Sutro Tower as a back-to-school activity each year. “When you see Sutro Tower, you’re home.”

Chicago's Willis Tower and New York's Empire State Building are among other iconic sites with consolidated broadcast facilities. Hmelar describes Sutro as Empire’s “artsy cousin.” Its unique design features one tower and one building, unlike structures with towers atop office or residential spaces. The closest analogy is perhaps Paris's Eiffel Tower, hosting multiple broadcasters in one location, though Sutro lacks tourist amenities.

There have also been numerous earthquake warnings that have been transmitted via its host signals, most notably 1989’s Loma Prieta, which registered 6.9 on the Richter scale.

Former Sutro spokesman Dave Hyams noted the reason the tower withstood the quake — two of the three KGO(AM) towers did not — is the structural science behind it. The tower is embedded in 15 million pounds of cement.

There are seven generators and an associated fuel supply that can keep equipment running for up to three days without power.

Velez noted that maintenance is a constant part of the process. In 2025 that included the repainting of cladding panels.

Sutro removed vertical cladding to comply with seismic code. Inside panels are now thicker to improve rigidity, which also allowed the panels to be painted offsite. The outside horizontal cladding panels are next, and Velez expects the paint job to be completed by 2027.

Velez’s duties are not without stress. “I dealt with more lawyers in the first year I was here than in my previous 50 years of existence,” he cracked. But by all accounts, the relationship between the 977-foot tower and its neighbors is as good as it has ever been. He credits the team at the law firm Womble Bond Dickinson and at Lighthouse Public Affairs for improving communications between the neighbors and the city of San Francisco.

“We’re here, I can be reached 24 hours a day,” he said.

And if you look up in the City by the Bay, you’ll get a glimpse of the tower, peeking through the fog.

ABILENE. Texas—A severe storm knocked down the tower and severely damaged the news studio and main facility of Sinclair-owned KTXS here on Sunday, June 8.

“At approximately 11 p.m. on June 8 during a severe weather event, a tornado struck the KTXS facility, causing significant damage, destroying our tower and impacting much of the building,” the ABC affiliate, which broadcasts on Channel 12, reported on its website. “We are thankful there were no injuries at the station. Our team is working quickly to assess the damage and find a solution to bring KTXS back on air as soon as possible.”

Sinclair told TV Tech that KTXS “was back on the air (modified) by Wednesday a.m. with an assist from our San Antonio station and equipment brought in from other Sinclair stations."

The station also reported that its newsroom was working from Abilene Christian University.

Local meteorologists recounted the terrifying moment when the storm tore off the station’s roof here.

“Quite literally, our studio roof was ripped off its hinges, if you will,“ KTXS meteorologist Caiden Dinkins said, “Our studio roof just blew off right above me and our chief meteorologist, Mark Rowlett, as we were trying to take cover from kind of an unexpected situation."

The station also reported that weather officials said “peak winds are estimated at 90 miles per hour in Abilene. The 199-foot KTXS broadcast tower was bent and knocked over onto the roof and across the property, while the base remained intact. A large rooftop air conditioning unit was blown by strong winds, likely contributing to a roof collapse and a partial brick wall failure in the station’s garage.”

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Stainless, which has provided towers and structures for thousands of broadcasters and other businesses since 1947, will cease operations.

President Gregg Fehrman said parent company FDH Infrastructure Services has decided to discontinue the brand, which it acquired nine years ago.

“The company plans to auction off all field equipment. In addition, FDH ownership is looking to sell off all historical data on its projects over 77 years,” he wrote in an email to Radio World.

Fehrman says “60% of the [Stainless] personnel have moved on, with the remainder around until the end of the month.” He said his last day with the company will most likely be in early November.

The company cites its involvement in 15,900 projects spanning from 1947 to the present, covering over 7,250 Stainless-built structures and more than 900 towers built by others.

[Related: “Mizzou Builds a New Tower for Its FM and TV”]

In the email to its customers announcing the decision to cease operations, Stainless says ownership will “sell either copies of the documentation or exclusive rights for same documentation on each tower number. Information will not be parsed. If copies are requested, the whole file/history will be released for each tower project number. Ownership will also entertain selling all project and standards data together for one purchase price,” the email stated.

Interested parties can reach out to Fehrman at gregg.fehrman@fdh-is.com.

Long History
Stainless was founded in 1947 by Walter L. Guzewicz, Henry J. Guzewicz and Richard J. Eberle, according to its website, and built its first tower in Philadelphia for radio station WJMU. That tower was in Delair, N.J., an insulated 385-foot guyed structure topped with an RCA pylon antenna, according to the history timeline.

In 1950 the company constructed its first 500-foot towers as part of a four-tower array for KCBS (AM) in San Francisco.

In the early 1950s, Stainless designed and fabricated Empire State Building test towers for RCA. Empire’s unique mast had to be duplicated on the ground for electronic testing purposes at RCA’s facilities in Camden, New Jersey.

Stainless designed and fabricated its first 1,000-foot TV tower for General Electric in Reading, Pennsylvania. The trussed-leg tower was billed as the “home of the world’s most powerful TV station” at the time and was one of only three 1,000-foot towers in the United States.

The company designed and fabricated towers used in atomic testing in Nevada in 1955. The Type G-15-100 towers were placed at varying distances from the point of detonation.

Stainless has gone through several ownership changes. In 1999 it was purchased by SpectraSite Communications and renamed SpectraSite Broadcast Group. In 2004 the company was acquired by Don Doty and Pat Moore and renamed Stainless.

FDH acquired Doty Moore Tower Services in 2013 and acquired the assets of Stainless LLC in 2015. That acquisition included more than 7,500 structural drawings representing work Stainless had done for the radio, television, microwave and general communications industry since 1947.

At that time, FDH said that as many as half of the broadcast towers standing in the United States had been fabricated by Stainless LLC.

FDH does engineering investigation of structures and foundations, according to its website. It is headquartered in Raleigh, N.C., and has offices in Florida, Illinois, Texas and Wyoming.

The most recent entry on the timeline says Stainless celebrated “75 years of innovative tall tower design, safety and reliability” in 2022.

This article originally appeared on TV Tech sister brand Radio World.

MANASSAS, Va.—Thermal cameras and contactless spot thermometers are increasingly being used at the station level to safely check electrical wiring, power systems, HVAC equipment, and transmitters. Camera-equipped drones (aka unmanned aircraft systems or “UAS”), have been found to be incredibly useful in documenting tower-mounted equipment and providing a “first look” at suspected antenna, tower, or transmission line problems, saving tower crew cost and time.

At Cavell Mertz, we have found thermal cameras to be helpful in spotting transmission line problems (with bullet junctions and elbows being the usual suspects) since the line can be thermally scanned while it is being fed by the transmitter at full power (Fig. 1). A network analyzer may sometimes not “see” a problem until it significantly worsens since the network analyzer operates at very low power. A problem or failure that is happening while in operation or under load may not be apparent unless it’s being stressed at higher powers. 

Cost-Effective Solution
IR cameras are typically used at ground level for locations such as the inside of a transmitter building, along the transmission line trestle/ice bridge, at the tower base, and in the first few feet up the tower. Getting useful images further up the tower with ground-based cameras isn’t as feasible, as telephoto thermal lenses and camera equipment capable of providing usable, reliable information at longer distances (further up the tower) are extremely expensive to purchase or lease. Nevertheless, in the early days of doing IR scanning for clients, we leased nitrogen-cooled long lens systems in order to chase down problems on a tower that were evading diagnosis. 

As thermal cameras have become smaller, lighter, and (somewhat) more affordable, drone systems also became more reliable, precisely controllable, and able to lift heavier loads—all of which resulted in a “perfect marriage” of capabilities—airborne thermal cameras that can scan tower-mounted lines and equipment from more favorable vantage points.

Over the years, as we first built our own drones, then bought capable large commercial models to support our airborne antenna RF measurement work, we started experimenting with drone-mounted IR systems, finally settling on a camera system that provided dual IR/visual images while having lenses and sensors that permitted tower scanning from a reasonable distance from the tower. We ended up with three drones that can carry multi-use camera payloads. 

Plan Your Flight
Scanning a tower requires a bit of pre-planning and a careful preflight: guy wires, T-bars, and candelabra arms have to be avoided, and wind must be taken into account to prevent a collision (note: in a collision, the drone always loses, so inattention and distraction must be avoided during a mission). Some drones have a failsafe system, where it self-navigates to a safe place should it lose control telemetry.  Be sure that your ”fly-away” plan takes the drone out and away from the tower, and into a safe (guy wire-free) zone (Fig. 2).

Take a close look as to what is emitting RF energy on the tower, at what frequency, and at what power, especially in “tower farm” situations. Many drones don’t tolerate RF saturation or interference/overloading of their control and telemetry systems and some unlicensed microwave frequencies are close to the Wi-Fi telemetry frequencies used by drones. You could lose control and  have an un-commanded “fly away” event or crash.  

Since you want to see all systems being measured operate at full power for diagnostic purposes, plan to fly farther from the tower as the UAS flies through the elevations where high RF is expected. We typically fly close to the tower as we scan transmission lines, then back away to a calculated safe distance to transit a hot area (while still scanning the area of importance), then navigate back to the closer position once the UAV is out of the RF hot zone. Obviously, this is not a single operator event—you’ll want spotters to assist you. Understandably, this requires skill, planning, and satisfaction of certain FAA requirements.

Gathering and Analyzing Data
As for the practical side of gathering data, if your drone system doesn’t have the ability to record height as it ascends to correlate a height with a hotspot, look at the tower drawings and note vertical benchmarks, such as known guy wire and antenna heights. This way, if a thermal hot spot is noted, you can tell a tower climber to start checking for issues at a particular height range, saving some of their time.

Since the sun can thermally “load up” the tower, we prefer to do thermal scans at night, allowing time for the tower to cool down; otherwise, the solar loading can make temperature differences difficult to spot. Wind speeds and temperatures can differ, often significantly, as the height above ground changes. Having access to good weather information and on-board sensors can be helpful as you evaluate the resulting images and data.  

As for interpreting the information, training and experience are key. From a thermography standpoint, operating IR equipment from a drone is similar to operating IR equipment on the ground—the same data interpretation principles apply, even though the environment and considerations differ. Thermal camera suppliers such as FLIR have training programs and videos (including IR drone training) available. From experience, we know that small differences in temperature gradient generally are normal—it is the big differences that are telling. Reflected heat and light, paint color, and even material type and finish can give a false indication of high, or even normal, temperatures. 

Finally, if an anomaly is suspected from the imaging (Fig. 3), some people skills are needed to discuss what was observed and as a plan of further investigation is being developed. After all, thermal imaging is an interpretative art as much as it is a science. Approaching a possible problem in a non-confrontational manner with the suppliers and installers can go a long way toward gaining cooperation and a resolution. 

ALEXANDRIA, Va.—Tower and wireless infrastructure company InSite Wireless Group has announced that it has entered into a management agreement with TV broadcast group Tegna, in which it will provide operational support and marketing services to Tegna’s wholly owned broadcast towers.

“Working with InSite will improve our ability to support, maintain and monetize our Tegna owned broadcast towers,” said Robert Lydick, vice president of information technology and station operations for Tegna.

“We are excited to be working with the Tegna team to create greater asset value for their sites while safeguarding these mission critical assets,” added David Denton, senior vice president for broadcast with InSite.

Tegna has 51 television stations and four radio stations in 43 markets across the U.S.