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American Tower Claims a First in Digital TV Broadcasting

By Don Bishop, Exec. Editor, Assoc. Publisher, AGL Magazine

The Dallas-Fort Worth digital TV single-frequency network at American Tower sites uses Comark Parallax transmitters. Source: Hitachi-Comark.

American Tower is playing a role in the next generation of TV broadcasting technology that may lead to lucrative uses for the towers it owns that already serve mobile communications network operators, such as AT&T Mobility, Sprint, Verizon Wireless and T-Mobile US, along with some towers that serve TV broadcast stations. With TV stations having not long ago completed a compulsory transition from analog to digital broadcasting, they next may participate in a voluntary program to add another form of digital broadcasting. Called ATSC 3.0, the technology uses a single-frequency network of multiple transmitter sites in a given market — which is where American Tower comes in.

Digital TV transmitters in a single-frequency network may emit as much as 100 kilowatts of power, much higher than the 100 watts of power that many cellular transmitters on towers emit. Adding sufficient three-phase AC power and adequate shelter space for TV transmitting equipment at cell sites makes the use of many typical cell sites problematic without major changes. To serve the Dallas-Fort Worth TV market, American Tower built what its newsletter, BroadcastBuzz, says is the first market-wide network of four towers for testing the new digital broadcasting technology.

Plans announced earlier for the project stated that the testing would air programming from KXTD-TV, owned by Cunningham Communications, and KSTR-DT, owned by UniMás.

American Tower upgraded electrical power, fiber-optic cable connectivity and transmitter buildings at three cell towers in Fort Worth, Denton and Garland, Texas. The fourth location in Cedar Hills, Texas, already has a TV transmitting facility with the necessary AC power and shelter capacity.

“All sites underwent upgrades for networking, internet exchange, fiber, and data center connectivity, in addition to being upgraded to three-phase power,” the newsletter reads. “Each site implemented Comark transmitters and exciters and was built to enable scalability and replication of design for future deployments.”

Ed Tiongson, director of product innovation for American Tower, offered these comments in the newsletter: “The construction phase went quite smoothly. With these ATSC 3.0 deployments, it’s critical to draw on expertise to synchronize single-frequency network towers effectively, including integrating the network components, such as antennas, transmitters and radios for optimum signal delivery.”

The next phase of the project consists of validating the radio-frequency design and link budget through drive tests and gathering data, the newsletter said. It said that the project team will work through operational workflows for management of a market-wide single-frequency network.

The newsletter quoted Jim Leifer, senior manager of broadcast operations at American Tower: “Having the scale and expertise to develop a plan to completion is one of the strengths we offer to our partners. Once the RF measurements are validated, we will be able to scale for additional sites in the future as business needs dictate.”

American Tower’s partners in the Dallas-Fort Worth project include Sinclair Broadcast Group and Nexstar Media Group, owners of multiple TV stations and the founders of the Spectrum Consortium, a membership organization formed to lead the transition to ATSC 3.0 digital TV broadcasting. TV station owners Univision Local Media and Cunningham Broadcasting brought their Dallas TV channels to the project, along with what will be a former TV channel after the TV broadcasting repack is completed. The third channel encompasses frequencies owned by Dish Network.

American Tower’s newsletter says that ATSC 3.0 digital broadcasting will provide many benefits to consumers, including dramatically improved over-the-air reception, immersive audio, deep-indoor reception, mobile reception, zoned programming and advertising, automotive services and advanced emergency alerting. TV broadcasters must be willing to embrace the new technology and spend the money necessary for its deployment even though receiver manufacturers are not required to produce TVs capable of receiving it, nor are the broadcasters themselves required to initiate ATSC 3.0 digital broadcasting.


SK Telecom, Sinclair Broadcast Group Sign Joint Venture Agreement

SK Telecom and Sinclair Broadcast Group have signed a joint venture agreement to lead the next-generation broadcasting solutions market in the U.S. and globally. The two companies will jointly fund and manage a joint venture company within the first quarter of this year.

The joint venture company will develop innovative broadcasting solutions based on ATSC 3.0, the next-generation broadcast transmission standard, with the aim to commercialize the solutions for the first time in the U.S. market in 2019.

ATSC 3.0 is the latest version of the Advanced Television Systems Committee (ATSC) standard. It will support several advancements including mobile viewing, 3D television, 4K Ultra High Definition (UHD), high dynamic range (HDR), high frame rate (HFR), and wide color gamut (WCG) picture quality, as well as immersive audio.

The commercialization of broadcasting solutions based on ATSC 3.0 – which enables data communications in broadcasting bands – will give rise to new services such as personalized advertisement and in-vehicle terrestrial TV broadcasting and map updates. It will also support two-way communication between broadcasting companies and user’s smartphone/vehicle/TV by recognizing user’s personal IP address.

SK Telecom and Sinclair anticipate all television broadcasting stations throughout the U.S. will adopt broadcasting solutions based on ATSC 3.0 within the next decade. Through the joint venture company, the two companies plan to actively provide ATSC 3.0 standards-based solutions to all U.S. broadcasting companies and seek other opportunities globally.

The joint venture agreement follows last year’s memorandum of understanding (MOU) signed between SK Telecom and Sinclair at CES 2018 to jointly develop leading technology for ATSC 3.0 broadcasting.

“SK Telecom will work closely with Sinclair Broadcast Group to gain leadership in the next-generation broadcasting solutions market in the U.S.,” said Park Jung-ho, President and CEO of SK Telecom.

“Sinclair is excited to partner with SK Telecom, a wireless technology leader, to explore and commercialize solutions that optimize the economic value of our spectrum, our broadcast infrastructure, our programming ventures and our emerging OTT platforms. Bringing these assets together in a converged broadcast/broadband platform environment will be a significant value multiplier,” commented Chris Ripley, President and CEO of Sinclair.

Hope for Overstressed Guyed Towers and Their Owners

The load path transfer method is a new way of reinforcing overstressed towers, enabling carriers to upgrade antennas and electronics, where it formerly seemed impossible.

By Tom Swan

With today’s seemingly endless proliferation of new wireless spectrum, the prospects for wireless tower owners seem glowing. Local communities, on the other hand, are adopting more codes and regulations that oppose new tower site development. Although citizens crave the expansive use of wireless technology, they would prefer it if wireless didn’t require towers. For these reasons, the collocation of antennas on existing structures is strongly promoted.

A one-third scale model with orange members that represent load path transfer method (LPTM) augmentation.

A one-third scale model with orange members that represent load path transfer method augmentation.

Tower owners are happy to welcome new tenants and added rental revenue. But prior to approval of a tower collocation, best practices dictate that towers be meticulously mapped and a structural analysis be performed to assess the current loading of antennas, mounts and cables.

Available tower space can also be deceptively burdened by a carrier trend of adding many hundreds of pounds of tower-mounted equipment adjacent to antennas. This trend has significantly increased tower loading. More and more, the structural evaluation process concludes that a tower is already overstressed. That means the collocation of new carrier facilities cannot proceed.

Several factors have contributed to this unfortunate condition. On older towers, the process of reinforcement by attaching additional structural members has often done more harm than good. Holes were drilled and members were welded, weakening the structures and promoting corrosion. EIA/TIA safety standards for ice and wind loading have also been modified, making them more stringent. Prior to the introduction of PCS cellular technology, and more recently LTE cellular technology, towers were built to a minimal standard without forethought to advancing industry requirements. Towers needed to be taller and stronger, but budgets prevailed.

An LPTM internally inverted truncated cone base attachment.

An LPTM internally inverted truncated cone base attachment.

Moreover, tower properties have been repeatedly sold to a succession of buyers, and records haven’t always made the transition to new owners. Structural analysis requirements have sometimes been circumvented while defunct antennas, supports and cables have not been removed.

Drop and Swap

Tower suppliers have a simple solution to this problem: drop and swap. Tower steel suppliers would never hold it against the tower owner for undersizing its requirement for a previous tower. They will simply deliver new steel. It’s not a problem at all.

But, wait. What if the community prefers the view with the old tower missing? Will jurisdictions approve the erection of a new, larger tower? How long will tenants be off the air? Will state historic preservation officers want to talk about “invisibility?” How about National Environmental Policy Act considerations? What will the Federal Aviation Administration want to know? Will birdwatchers protest?

Structural Reinforcement

Through the years, various methods of structural reinforcement have been tried with mixed success. They include removing and replacing overstressed or corroded members, or building up existing members. Adding strength by welding split sleeves to legs is costly. Many contractors, citing safety concerns, have ceased offering that option.

One solution encloses the existing tower in another tower or a portion of a tower. This exterior tower wrap is expensive and usually requires the relocation of mounts and antennas, and the rerouting of cables and ladders. Often, expensive foundation modifications are also required.

A Tower Within a Tower

The load path transfer method (LPTM) for strengthening a tower is nearly self-defining. LPTM relieves the load from each tower section’s legs by combining and delivering those loads to the tower’s foundation using a pre-engineered internal tower structure that’s assembled on-site. Once installed, a patented turnbuckle function tensions the combined structures from top to bottom. Each LPTM augmentation is designed for a specific tower. There is no welding. There is no drilling.

In most cases, antennas, mounts, cables and ladders need not be moved. Equipment remains on the air during the entire process. Also, depending on the jurisdiction, most LPTM projects require little or no additional zoning or permitting.

It is unfortunate that many professionally designed tower structures are being unnecessarily replaced. Tower professionals who followed all the right steps find that with the changing of rules or the evolution of technology, the value of their good work is depreciated. Now it is possible to add significant life to older towers.

First, let’s consider whether a tower is a good candidate for LPTM.

Foundation, Anchors and Guys

Given a few criteria, a well-designed and maintained tower and anchor foundation system can typically be used in an altered tower application, possibly with new guy wires at existing or different positions.

The original design and the construction should be inspected and documented. It is important to thoroughly inspect the anchor foundations and verify that installation was completed in accordance with the design. Extremely important: What is the condition of the anchors? Guy wire and anchor hardware corrosion that has occurred because of a lack of cathodic protection can be a problem.

A turnkey LPTM installation.

A turnkey LPTM installation.

Installing LPTM Components

The tower must be sound and climbable for an LPTM augmentation to proceed. Ideally, the tower face width should be at least 36 inches, providing ample room for workers to install LPTM components. LPTM essentially becomes a tower within a tower.

Beginning the Process

The first step in determining the feasibility for an LPTM project is to map the tower and its foundation. The mapping process is a tower owner’s necessary tool and is the basis for the LPTM design and quotation process. The resulting information is entered into a proprietary database written specifically for the LPTM. Database reports are used to develop a scope of work, a list of materials and the individual design of necessary components. The output will also generate the estimated end result of the process. At this point, the tower owner will know how its tower will benefit from LPTM and will receive a close estimate of the project’s cost.

LPTM Augmentation Examples

Oriental, North Carolina: The project involved a 480-foot guyed tower. A structural evaluation determined the feasibility of Verizon and AT&T each adding LTE overlays. Considering the proposed additions, the structural analysis indicated a 222.8 percent structural loading. An LPTM retrofit was shown to provide a low-cost, time-saving solution.

Along with the custom-designed LPTM augmentation, the project included removing the top 120-foot secondary tower addition, replacing existing guy wires, and adding a torque arm and an additional guy level.

After adding LTE overlays, the result was a 360-foot tower with a load rating of 78 percent.

Hawthorne, Florida: Near Gainesville, Florida, the project in Hawthorne was a 40-year-old, 480-foot guyed tower on which AT&T wanted to add LTE overlay equipment. Mapping and structural analysis indicated that the result would be a 228 percent structural overload. LPTM augmentation was recommended.

The tower’s top 180-foot portion was removed. Workers performed rust abatement, applied cold galvanizing and removed two tower leg structural modifications that were previously installed.

After the AT&T overlay was installed, an updated structural analysis showed a load rating of 63 percent.


The load path transfer method is a proven solution. Its results have been well documented.  Tower owners now have a reasonable alternative to high-cost tower replacement.

Tom Swan is national sales manager at Hemphill in Tulsa, Oklahoma. Hemphill manufactures LPTM components. His email address is Send Mail

 tswan@hemphill.com. Keypoint Construction of Mandeville, Louisiana, is the sole licensee of LPTM technology. At Keypoint, information is available from Dick Huddleston, managing partner. His email address is Send Mail 

For more information, go to www.hemphillbts.com/Towers/index.html


Industry Vets to Drive Vertical Bridge Broadcast Towers into New Territory

By J. Sharpe Smith —

June 18, 2015 — Don’t expect the status quo from the two veteran broadcast industry executives who were appointed recently by Vertical Bridge to oversee development of the firm’s broadcast towers. Mark Stennett, with 30 years of engineering roles in broadcast radio, was named senior broadcast engineer, and Gary Hess, previously with iHeartRadio and American Tower, was appointed vice president of broadcast towers leasing; they are open to the possibilities.

Broadcast towers may not be the subject of a lot of hype, but they represent prime vertical real estate. Hess and Stennett are clearly excited about the prospects of creatively putting that space to work. The two will manage the portfolio of 411 broadcast towers Vertical Bridge purchased from iHeartRadio in December 2014.

In particular, Hess is looking to unlock the additional value in these towers through innovative methods such as diplexing and aggregating AM towers, which he was not allowed to do at his previous jobs leasing for the broadcast tower industry.

“I am finding that diplexing and aggregating AM towers, moving an AM radio station to another site and freeing up the first site for real estate use is quite an attractive offer,” Hess said. “This is the first time that I have had all of these assets and all of these opportunities in a job. These towers are open to all opportunities.”

Vertical Bridge’s diverse portfolio of towers with FM, AM and television antennas represents a challenge, according to Stennett. “It is one of very intense engineering,” he said. “It is not uncommon to have multiple FM carriers running through a combiner to share a common antenna.”

Vertical Bridge will be charting new territory with respect to adding tenants to AM towers, where the tower is the antenna and it represents a challenge adding additional antennas.

“It is not impossible, but it is tedious. It involves installing equipment to avoid shorting out the AM antenna,” Stennett said. With respect to the high power levels used, Vertical Bridge enforces different climbing procedures to cope with concerns about RF exposure levels.

Vertical Bridge Preparing for TV Repack

Vertical Bridge is gearing up for the FCC’s incentive auction of television broadcast spectrum, which will permit TV broadcasters to either voluntarily go off the air, share their spectrum or move to other channels in exchange for part of the proceeds from auctioning their spectrum to wireless providers.

Vertical Bridge’s portfolio includes full-power television stations with towers up to 2,000 feet in height, and Hess said he is looking forward to the process of reassigning broadcast TV channels to free up contiguous blocks of spectrum for wireless broadband, known as TV repack. Vertical Bridge has committed capital to it and possibly master antennas, according to Hess.

“[TV repack] is going to completely rebuild this industry. It’s a big job. I think you are going to see new efficiencies, lighter antennas, and more stations combining and operating in a single system that is provided by the tower owner. We want our share of that activity,” he said.

Tower Manufacturer Stainless Sells Fab Plant

After 66 years as a manufacturer of radio towers, Stainless, headquartered in Wales, Penn., has closed its Pine Forge, Penn., fabrication plant.

The reduced demand for tall tower fabrication has forced the company to redirect its efforts away from tall tower manufacturing, according to Gregg Fehrman, president and chief engineer, on the company website. In this economic environment where lean and mean is the new manufacturing model, under-performing assets cannot be retained indefinitely, according to the statement.

Don Doty, founder of Stainless, emphasized that the company will continue to do engineering, detailing, fab and installation, but the fabrication itself will be farmed out. Stainless will continue to offer fabrication services through qualified vendors, as well as retain key personnel from their fabrication division to monitor quality assurance and quality control through these vendors’ facilities.

This move repositions the company so it can remain a significant player in the broadcast tower industry.  Since the initial announcement in mid-September, the company has since auctioned off all of the equipment, tooling and raw materials as well as the physical property itself. This direction is seen as a move for the company to retain the control and accuracy of its manufacturing quality without the overhead of in-house fabrication. It claims that its engineering and construction services divisions remain strong and healthy, and capable of continuing to provide all the services they have previously offered.

According to one industry source, Stainless was virtually the only option for stations that required towers in the 2,000+ foot range height. Such tall towers are mainly deployed in the Midwest, as well as countries where the topography is largely flat. The extreme height is needed to be able to provide adequate coverage over such sprawling landscapes. Unfortunately, much of the build-out throughout this part of the country, and many other developed countries, has been completed.

Broadcast tower manufacturers began to struggle with the conversion to digital television.  Because television is a government-regulated industry, tower makers were subject to the whim of the ebbs and tides, as well as well as the politics, of the transition. For a time it was pretty much a roller-coaster ride that followed the business cycles associated with the DTV transition.

But the death knell of broadcast tower fabrication came shortly after the June 2009 transition, when the FCC proposed reassigning 40 percent of the remaining broadcast TV spectrum to wireless broadband, in anticipation of the upcoming onslaught of data that was predicted to occur as the century turned. Once that was inked, orders for tower modification and new construction began to plummet and then screeched to a halt when the FCC ended up putting a freeze on all new full-power and Class A TV station modification applications.

At that point, Stainless’ number took a 60 percent hit, almost overnight. What sounded the death knell for the fab was that, unlike the previous cycles, there was a lot up in the air. The expected data tsunami had everyone scratching their heads on how to prepare for it and that meant there was a lot of uncertainty as to what was going to happen to what spectrum, where. There was no way for Stainless to know how this would turn out because, in the DTV domain,  there were no solid numbers to determine how many stations would voluntarily relinquish spectrum for the tentative 2014 incentive auction designed to free up licenses for broadband.

Ultimately, what that meant was that there was no way to forecast how many stations would require tower modifications to move to another channel assignment. That was just too much unknown information, and it didn’t make sense to absorb the costs of the fab and keep it open.

In another vein, and on the cellular site, it is estimated that 70 percent of cell sites, going forward, will be of the small cell variety. Small cells have a completely different dynamic, in terms of deployment, than macro or TV/radio towers and do not require behemoth towers. This also does not bode well for Stainless and other large-scale tower manufacturers.

Over the years, Stainless estimates that it has supplied more than 7,500 towers in 100 countries, including around half of those used for broadcasting, in the United States, since it started producing towers in 1947. The fab plant is located in an area with a 300-year history in ironworks, which started with the discovery of iron ore deposits in the mid 1700’s – ah…times they are a-changing…