The Society of Broadcast Engineers has announced the recipients of the 2025 SBE National Awards, which recognize outstanding achievements by individual members, local chapters, and Sustaining Member companies. Among the organization's highest honors are the Robert W. Flanders SBE Engineer of the Year and the James C. Wulliman SBE Educator of the Year awards.

Doug Irwin, CPBE, AMD, DRB, of Burbank, CA, a member of SBE Chapter 47 Los Angeles, has been named the 2025 Robert W. Flanders SBE Engineer of the Year. With nearly four decades of experience on both coasts, Irwin manages one of the most complex and influential radio operations in the country.

His career has navigated the challenges of industry consolidation and evolving technologies, yet he remains deeply committed to advancing engineering standards and mentoring the next generation of professionals. As one Chapter 47 member stated, "Doug exemplifies unwavering dedication and genuine passion for broadcast engineering."

In addition to serving as the regional engineering lead for iHeartMedia Los Angeles, Irwin is also a longtime consultant and contributor to TV Tech sister brand, Radio World.

David Bialik, CBT, of New City, NY, a member of SBE Chapter 15 New York City, is the recipient of the 2025 James C. Wulliman SBE Educator of the Year award. An SBE member for 15 years, Bialik played a key role in organizing the 2024 and 2025 Ennes Workshops covering Media Over IP, held during the NAB Show. He also serves on the SBE Education Committee and is co-chair of the AES Technical Committee for Broadcast and Online Delivery.

Currently serving as the director of engineering for MediaCo NY, Bialik is a frequent contributor to Radio World. You can read some of his columns here.

Blackmagic Design has received the SBE Technology Award for its DeckLink IP 100G, a PCIe Gen 4 card capable of capturing and playing back up to eight channels of HD and Ultra HD video simultaneously within SMPTE 2110 IP systems. This marks the company's fifth win in this category. DeckLink IP cards are designed for seamless integration with IP-based broadcast infrastructures, offering high-performance, multi-channel video workflows.

Mark Lee of Compass Media, based in the Cayman Islands, has been awarded the Facility Innovation of the Year award. In a groundbreaking effort, Compass Media extended its WheatNet-IP audio network across 85 miles of underwater fiber to link its four radio stations with the two smaller Cayman Islands. This achievement significantly enhances media access and connectivity across the region, uniting communities through broadcast for the first time on this scale.

For the fourth consecutive year, SBE Chapter 15 New York, NY, has been recognized with the Best Chapter Communication Award. Rather than relying solely on a traditional newsletter, Chapter 15 effectively engages its members through a variety of platforms, including email, the chapter website (sbe15.com), Twitter, Facebook, and Zoom.

The Wisconsin SBE Chapters, in partnership with the 2024 Wisconsin Broadcasters Association (WBA) Media Technology Institute, have been honored with the award for Best Chapter or Regional Educational Event. The annual three-day institute, held in June, provides a comprehensive and immersive learning experience designed to support the professional development of broadcast engineers at all career stages.

With the announcement, SBE Awards Committee Chair Terry Douds, CPBE, said, "Recognition and encouragement of outstanding efforts of SBE members is a key part of the SBE's mission. Congratulations to all the award recipients."

The recipients will be recognized during the SBE Awards Dinner held at the SBE National Meeting, Sept. 24-25 during the Midwest Broadcast and Multimedia Technology Conference, presented by the state broadcast associations of Ohio, Indiana, Kentucky, Michigan and Pennsylvania.

The Virginia Association of Broadcasters has recognized Bill Sewell, Director of Engineering at WTKR & WGNT in Norfolk, Va. as the recipient of the 2025 J.J. Freeman Engineering Achievement Award. The award honors those “who have made an outstanding contribution to broadcasting and who have shown technical knowledge, dedication, dependability and leadership in broadcast engineering affairs,” according to the VAB.

From the VAB:

Bill Sewell is the Director of Engineering at WTKR & WGNT in Norfolk, Virginia. A native of Louisville, KY, he fell in love with TV news while working in college as a part-time production assistant at WAVE-TV (NBC, Gray Media). He attended the University of Louisville, where he graduated with a degree in MIS in 2002.

At some point along the way, he realized that his interests in both broadcast production and computer science could actually merge into a career. He transitioned into the engineering & IT department at WAVE in 2001, eventually moving to Norfolk to take the Chief Engineer position at WTKR in 2010.

He is an alumnus of the 2017 VAB Best of the Best class and is the current president of the Society of Broadcast Engineers, chapter 54. He and his wife of 20 years, Melanie, have three children—Sam, 16; Griffin, 12, and Maisy, 10.

Don Everist, a well-known figure among our broadcast engineering circles, has died, according to reports from his colleagues.

Everist was a registered professional engineer and principal at the engineering consulting firm Cohen, Dippell and Everist P.C., which specializes in broadcast radio and television design and licensing.

Bob Weller, vice president of spectrum policy at the National Association of Broadcasters, confirmed Everist passed unexpectedly last Wednesday after years of service to the industry. According to the firm, Everist kicked off his D.C. engineering career in 1967.

“Together with Julius Cohen and Ralph Dippell, Don founded the CDE firm to serve the consulting engineering needs of broadcasters,” Weller told Radio World. “CDE is the last such firm actually located in the District of Columbia. To this day, Don and CDE have been active in FCC proceedings involving broadcast and in the service of their many clients.”

Thomas Locke, a consultant at Cohen, Dippell and Everist, said Everist was hired in 1961 by George C. Davis, Consulting Engineers, Radio-Television, and worked for that firm and its predecessors—which includes Cohen, Dippell, and Everist, P.C.—continuously until his passing.

Locke said Everist was a longtime member of various engineering organizations, including the Institute of Electrical and Electronic Engineers, the Society of Professional Engineers and the Illinois Society of Professional Engineers, to name a few.

Everist was also a member of the Association of Federal Communications Consulting Engineers which, according to its website, monitors the engineering policies of the FCC to ensure that the agency’s regulations coincide as closely as possible with sound engineering principles. He previously was the association’s director and treasurer, a role that Weller now holds.

Michele West of Cohen, Dippell and Everist said in an email that Everist was a U.S. delegate multiple times in international planning sessions. She said there are no further details on his obituary at this time.

Friends and former colleagues of Everist are sharing statements with Radio World as news of his passing spreads.

“Don Everist was an exemplary engineer, a thoughtful and helpful colleague and a good friend for many years,” said Ben Dawson, a senior consultant at Hatfield & Dawson Consulting Engineers, in an email.

Everist’s wife Sandra passed in 2020.

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

As engineers experienced in designing today’s broadcast facilities, we are careful to coordinate every detail of design as it relates to the architecture of sports and entertainment facilities. Every aspect is analyzed to ensure the fan experience is optimized. It’s important because there are thousands of screaming fans in your stadium, but there are also millions of passionate fans watching on television. We take extreme care when designing the physical space. 

Likewise, broadcast designers have a critical role in maximizing the viewing experience for those around the world. It’s also important to design a facility with the onsite broadcast needs in mind. Backed by our experience at large-scale venues, we share three common mistakes that can be avoided with thoughtful engagement by your broadcast design professionals.

Failure to Verify Cabling Runs

Have all the critical termination locations in your facility been determined? Has your broadcast designer considered the conduit pathways between all of these locations? If they haven’t, then you may end up with inadequate camera support or communication challenges for the TV production crew. Review of these cabling runs will also help eliminate unnecessary cabling or incorrect cable types – saving your client significant amounts of money and eliminating huge headaches for production crews when it’s time to go live!

Broadcast design professionals should properly specify their pre-wire and backbone cabling systems. If not, your stadium crews could be forced to run unsightly bundles along the floor, over the roof, or through occupied spaces for each event. Getting this right is vital.

Technology is adapting. Ask your broadcast professionals if the cabling specified is going to provide proper infrastructure — not only on opening day — but for the future technology that’s on its way.

Incorrect Camera Locations

An experienced broadcast designer will know the rules of camera placement by heart and follows the industry guidelines closely when laying out a facility. Failure to adhere to these rules could prevent the broadcast crew from capturing that game-changing moment or key replay angle. Here are some examples:

• For a soccer broadcast, the camera place to capture penalty box area footage should be on the 18-20-yard line, not the 25-30-yard line. The camera on the 18-yard line produces a much closer, clear, in-depth look than the one on the 25-yard line, even if that camera on the 25 has a better zoom lens.

• Leagues require specific camera angle ranges. For concourse level cameras, the shot angle should fall between 19 and 25 degrees from the playing surface. For press box and high end zone locations, the shot angle should not exceed 35 degrees.

A broadcast designer well-versed in league rules and regulations is an architect’s best partner when it comes to early stadium and venue planning. Camera placement is a well-informed art and a crucial factor in quality TV production.

Prime Real Estate for Broadcast Control Rooms

When it comes to event venues, everyone wants the best seat in the house. The midfield seats, center field plaza, club, and suite level locations are not only the highest revenue generators but are also the best location for a broadcast booth. A common myth in the industry is that the broadcast production crew and control rooms also need to be positioned at the center field suite level.

Here’s the inside knowledge your experienced broadcast designer should bring to the table:

• While many leagues require that broadcast booths be at midcourt, midfield, or the 50-yard line suite level, these same requirements don’t exist for control rooms. Networks realize the premium associated with these suite locations and will often help with the costs associated with the design and construction of these booths.
• Natural sound is very important for the in-game broadcasters and they need to be in the middle of the action to bring authenticity to the broadcast. On the contrary, control rooms work best in isolation from natural audio, which makes a remote location more ideal.
• From a cable management standpoint, locating the broadcast control room as close as possible to the TV trucks and cross connection room will save installation costs.

You may get recommendations from some in-house venue engineers to place the control room alongside the broadcast booth. While we don’t argue it’s a scenic location to go to work every day, it’s not necessary. A quality broadcast designer will apply best practices by keeping the whole organization in mind.

Avoiding these three common mistakes in broadcast design will help you deliver a thoughtful installation for your venue clients and help provide an awesome viewing experience to the people that matter most — the fans.

Top photo: Bud Walton Arena control room, University of Arkansas Razorbacks in Fayetteville.

Michael Tran is a senior broadcast designer for Henderson Engineers with nearly 30 years of industry experience. He has worked in venues around the country served as both a design consultant and broadcast engineer for networks such as Fox Sports and the NFL Network.

Brent Felten is an associate and lead program/project manager for Henderson’s broadcast services team. He started his career in stadium and arena design nearly 15 years ago. Since then, he has covered a broad range of practices with a proven track record of growth across all market sectors.

For more information, visit Henderson Engineers. 

The summer breeze brings a rise in temperature that can test equipment to its limits. As any on-call engineer knows, breakdowns sometimes come at the worst possible time. Air conditioners often fail at the peak of summer, when technicians are at their busiest attending to other customers who also have air conditioning issues.

One time, I was watching a replay of a basketball championship game at which the crowd changed “Beat the Heat” against the opposing team. Then a little later, I was in a place where there is neither game nor chanting. It was an emergency at the transmitter site, where the air conditioning system had broken down. That “Beat the Heat” chant seemed to have a whole new meaning.

As the temperature rose, the transmitter power modules were overheating. I needed to reduce the power, which at the time was not easy to do because of a problem with the exciter. I was finally able to reduce the power and prevent the overheating of the transmitter.

However, I sweated it out for one more day until we got a rental 20-ton A/C unit. This got our transmitter back to full power. (Yes, there are 20-ton air conditioners for rent — and they do the ductwork as well).

The building had two A/C units: a 10-ton and a 15-ton, for a total of 25 tons of total cooling capacity. With the 20-ton rental unit and the remaining 10-ton building unit, the total capacity increased to 30 tons, a little better than it normally was. But we still needed to find out the actual cooling capacity that was needed. This meant working with an air conditioning contractor.

DRAMA QUEEN

Among the transmitters of our TV network, this 15 kW DTV solid-state transmitter was the drama queen. There had been all kinds of failures since its installation in 2008. All 24 of the power modules had experienced some type of failure. The power supply also had seen failures, and there were a number of other issues throughout the years of use.

Then, as in a soap opera with a bad ending, the transmitter manufacturer went bankrupt.

In 2015, the transmitter site was assigned to me, and I had to dissect the cause of the problems one by one. One suspected cause of the failures was inadequate cooling inside the transmitter building. The 25-ton total cooling capacity was not enough because the flange temperature of the power transistors was on the high side and the surface-mounted capacitors on the pallets were burning up as well. The transmitter building originally had an analog klystron transmitter with the 10-ton A/C unit. The old transmitter was water-cooled while the solid-state was all air-cooled. They later added the 15-ton A/C unit.

In UHF, a solid-state transmitter is only about 18–22 percent efficient, needing a high airflow for cooling. Table 1 gives us a mental picture of how much higher the cooling and airflow requirement is for UHF compared to other devices of lower frequencies.

We can see that with comparable RF output of an FM transmitter, the UHF requires four times the airflow and more than ten times (an order of magnitude rise) in cooling capacity. Another consequence of high volume air-cooling is the noise level of the huge centrifugal fans.

CHOOSING THE A/C CONTRACTOR

Selecting the right contractor for a broadcast facility is crucial. Unfortunately, according to surveys, well over half of HVAC contractors do not size the cooling system correctly (which probably explains our problem). It is therefore important that we know how to get the right contractor and be knowledgeable enough on the subject matter as well.

A/C contractors have a rule of thumb when it comes to sizing air conditioners: Measure the floor area of the room; and from that, figure out the size of the air conditioner. This method does not work for transmitter buildings.

Then, as we know, there are stories going around about contractors. For example, some say scrupulous contractors would inflate the cooling load so that a bigger than necessary A/C unit would be installed.

According to Air Conditioning Contractors of America (ACCA), when sizing A/C units, contractors should be proficient in doing Manual J cooling load calculation and Manual S equipment selection. If your contractor is unfamiliar with these methods, you may need to look for another one.

MANUAL J LOAD CALCULATION

There are plenty of resources online on this topic. Software and apps make the calculations easier. The main thing is to make sure all heat loads are accounted for. There are two kinds of heat loads: sensible and latent heat loads. Sensible heat causes temperature rise inside the building (e.g. transmitter). On the other hand, latent heat is caused by the increase in the moisture content of the air inside the building (e.g. outside air infiltration in the building).

The intake-to-exhaust temperature difference and relative humidity are often overlooked in heat-producing equipment like a transmitter. To obtain these two values accurately, the measurements should be done during full-power testing at the factory. These measurements will help verify efficiency claims and will also help determine the amount of heat the transmitter blowers actually remove.

The sensible heat load equation is:

Air infiltration from outside brings both latent and sensible heat inside the building. If staff occupies the building, the human occupants also have latent and sensible heat loads. The total heat load is the sum of the sensible and latent heat:

During summer, a standalone building will receive solar radiation throughout the day. The east side will have peak radiation mid- to late-morning; the roof heat peaks at noon, and the west side peaks at mid-afternoon.

Then, if the walls are all made of concrete, the heat absorbed by the concrete will be released at night. For a given area of a concrete wall with length L and height H (both in feet), the heat equation is:

There are other possible sources of cooling load in a building; it is beyond the scope of this article to discuss all of them. However, we can look at a typical broadcast transmitter house as a sample problem.

A REAL-WORLD EXAMPLE

Let’s say we need an air conditioner for a new 30 kW FM transmitter. The cooling will not be supplemented with outside air. That is, all the cooling air is circulated inside the building (closed system).

The radiated solar heat on walls is calculated to be 35,000 BTU/hour while the rack equipment heat is 1,500 BTU/hour. Latent heat load amounts to 1,200 BTU/hour.

With 10.28 tons of cooling, the air conditioning system takes care of the entire heat load, even at the peak of summer. The transmitter manufacturer actually specified only 7.5 tons cooling capacity, but as we can see in this example, the required tonnage is much more than that.

In addition, when looking at the cooling capacity figures of the air conditioners, they specify the cooling in gross capacity. In actual application, net cooling capacity is used, not the gross cooling. Net cooling = Gross cooling – indoor blower heat.

From the cooling capacity table of a typical commercial unit, 10 tons would be inadequate, so we go to the next higher tonnage, which is 12.5 tons. A packaged-type cooling table would look something like Table 2.

With the extra cooling capacities on both sensible and latent, the 12.5 ton can meet the design condition of TR = 75° F, 50% RH and 95° F outdoor condition.

Manual S allows up to 15% overcapacity on TC. Ideally, a backup of the same size is also used. If there is no backup, an emergency exhaust system should probably be installed.

Selecting a properly-sized air conditioner is almost like an “imperfect” art because exact values cannot be obtained on each parameter. What is important is that the design conditions are met with some extra capacity, but not too much.

MIXED AIR AND EQUIPMENT SELECTION

Going back to the problem I began with in this article, tilt-up slabs of concrete 6.5 inches thick were used to construct the transmitter building. This was without insulation.

The exhaust air of the transmitter was ducted to the outside. This means that outside air was mixed with the supply air from the A/C, and this mixed air has a temperature somewhere in between the outside air temperature and the A/C supply air temperature. The incoming air also brings both latent and sensible heat. This kind of setup is called mixed air in the A/C contractor parlance.

When we were doing the calculations for the total heat load, it turned out that using mixed air was not the best setup for the high airflow rate that the transmitter requires. There are two main reasons:

First, a closed-loop (no outside air) would actually need a lower capacity A/C than the mixed air setup. Secondly, the summer latent heat from the outside air is very high. This is due to the high airflow requirement from the transmitter.

Humidity control becomes an issue with high latent loads. However, closed-loop means a very costly rework of the room infrastructure. We therefore decided not to change the physical set-up and concentrate on the A/C replacement only. Actually, commercial A/C installations very often use mixed air in their designs, but not at this much airflow of outside air.

The irony of mixed air is that “heat” from outside air was used to remove heat from inside the room.

At any rate, we decided to add a new 25-ton packaged air conditioner, and the total cooling capacity added up to 35 tons. A backup 25-ton unit was also considered. We chose the Rheem brand because we have good experience with their product. The new Rheem 25-ton unit was installed in August 2015. The building temperature and the power transistors flange temperature improved to an acceptable level.

As a broadcast engineer, you do not have to dread the summer heat when the cooling system is designed properly. All possible sources of heat need to be considered when doing heat load calculation; then use those figures to select the proper type and size of cooling equipment. Last, a competent contractor is crucial to the success of any project.

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RASTATT, GERMANY—To support its rapid growth in the U.S and Canada, Lawo—a global provider of network, audio, video and control solutions—has added Browning McCollum, David Desrochers, and Stanley Pan to its customer support specialists team for North America.

Browning McCollum, who joins Lawo as a Broadcast Technology Specialist, previously served as Viacom/Nashville’s Remote Engineer in Charge. McCollum, who is recognized for installing the first two Lawo mc296 mixing consoles, also won a 2016 Emmy Award for his work on “Grease Live.”

David Desrochers, CBNT, CBTE—the new Project Manager for Lawo North America—previously served as Chief Engineer and vice president of Engineering for The New England Sports Network, in Watertown, Massachusetts, where he designed, built and managed large-scale, mission-critical digital audio/video systems.

Stanley Pan—Lawo’s new Junior Network Architect—previously served as Network Solutions Engineer for Evertz, where he specialized in evolving IP technologies, including SMPTE 2110 interoperability testing.

Lawo recently opened a new support and logistics hub in Elmsford, New York with testing facilities, a training center and East Coast Sales and Support office, which complement the company’s New York City headquarters, West Coast Sales and Support office in Los Angeles, and Toronto, Canada headquarters.

WASHINGTON--Interested in a technical career at the Federal Communications Commission? Are you currently an engineering student or recent grad from an engineering school? If so, the new FCC Honors Engineer Program may be exactly what you are looking for.

The new program—intended to attract newly minted engineers to public policy work in the communications field—is a one-year career development program. At the end of the program, participants will be eligible for consideration for continued employment at the FCC.

“The digital revolution is rapidly transforming virtually every aspect of American life,” said FCC Chairman Ajit Pai said. “And it’s changing the FCC’s work, too. Many of the issues we confront today are technically complex.”

Honors Program engineers may work in several different areas, including:

· New communications technology and services, such as Next-Gen TV, 5G and the Internet of Things;

· Deployment of broadband service nationwide, including in rural areas;

· Finding technologies to improve communications services for all Americans, especially those with disabilities;

· Public safety communications technologies;

· Policy development to encourage innovation and investment in new communications devices and services.

The FCC will consider many criteria when evaluating candidates, including academic achievement, technical skills and extracurricular activities as well as a demonstrated interest in government service and/or the communications sector.

To learn more, visit the FCC website.

Figure 1

ALEXANDRIA, Va.—William H. Doherty was an engineer with Bell Telephone Laboratories in 1936 when he invented a circuit that used two tubes running in Class B configuration to act as a linear amplifier for radio transmitters. An earlier design that used Class B tubes was the push-pull configuration, which usually needed a transformer to combine the output of the two tubes (Figure 1). Push-pull was efficient and powerful, but it was not the end of the game for efficiency.

The Doherty amplifier didn’t need a transformer and boasted an efficiency advance over push-pull circuits. Although there have been many developments in amplifiers over the decades, some DNA from Doherty’s design is now making its way into modern television transmitters.

A typical Doherty amplifier configuration using tubes has them in common cathode mode, with one tube amplifying the bulk of the RF carrier (Class B or Class AB mode) and the other tube handling the peaks (Class C mode). The outputs of the two tubes are combined in a reactive network (Figure 2).

There were many refinements starting almost immediately, but Doherty amplifiers gave only a marginal efficiency boost in the era of analog radio and television broadcasting. The technology mostly was forgotten until the digital cell phone era began in the middle of the last decade, when it was discovered that Doherty designs gave an efficiency boost to virtually every form of digital cellular signal. The key is the higher peak-to-average ratio that digital transmission has in comparison to analog transmission.

Figure 2

With digital broadcasting and its higher peak-to-average ratios, Doherty amplification can result in up to a 14-percent efficiency improvement over more traditional amplification when driven by digital signals. That’s a serious improvement that was widely incorporated throughout the cellular industry.

HOW IT WORKS

One of the refinements to Doherty’s original circuit was to use one tube configured for Class AB operation and another for Class C. In both this and its classic design (two Class B amplifiers), a Doherty amplifier splits the input signal using a power divider and sends signal equally to each amplifier with a 90-degree phase difference.

On the input, the signal is split using a 3 dB quadrature coupler, such as a Lange or branchline hybrid (branchline is shown in our schematic). This is pretty much the same as the input to any balanced amplification scheme.

The output of the Doherty configuration is more complicated. Since the two signals are out of phase by 90 degrees, the addition of a quarter-wave transmission line on the output of the peaking amplifier will bring the two back into phase. They can then be combined using an R/C network.

The output of the combined amplifiers segments has the two in parallel, creating a Zout/2 impedance. This can be stepped up to Zout using a quarter-wave transformer. In a 50-Ohm system, the transformer needs to be 35.35 Ohms.

At lower-power operation, only the Class AB carrier amplifier functions and the Class C amplifier is dormant. Operating at these lower power levels, the Class AB carrier amplifier sees a modulated load impedance that results in higher efficiency and gain.

When the signal peaks, both amplifiers operate and both see load impedances that enable maximum power output. For digital modulation schemes that cause the exciter to spend much of its time at its modulation peak, the result is greater efficiency. At the power output of most digital television transmitters, that efficiency shows up immediately in lower operating costs.

Note that you get the efficiency advantage with a Doherty amplifier only at overall power levels that are backed off the maximum. Pushing a Doherty amplifier to maximum power eliminates the efficiency gain.

CHALLENGES

Although the inherent efficiency of the Doherty design makes a lot of sense in digital transmitters, an effective design presents some challenges. For one, a Doherty design is slightly less linear than a dual Class AB amplifier, which can result in higher distortion.

However, pre-correction and feed-forward linearization used in many transmitters can eliminate most of the linearity distortions, and good amplifier design can deal with the rest. And the really good news is that Doherty amplifier configurations work in solid-state designs as well as tubes.

Today, television transmitter manufacturers are building models with Doherty amplifiers, including Comark and Rohde & Schwarz. These are solid-state transmitters that can supply output power as high as 100 kW, with efficiencies that rival the best MSDC IOT transmitters.

For example, the Comark Parallax uses broadband 50-Volt LDMOS transistors in a Doherty configuration to provide up to 25 kW in a single rack cabinet. Adding cabinets can boost the Parallax’s power to 100 kW.

Rohde & Schwarz PMU901 Doherty amplifier module

Rohde & Schwarz has transmitter models for both UHF and VHF TV that use Doherty amplifiers, and also has Doherty technology in digital audio broadcasting products. The company’s THU9 UHF TV transmitter can deliver up to 50 kW using 48 amplifier modules.

Since the dawn of broadcasting, continuous advances in efficiency have meant that the next generation of transmitters is always the most efficient. Couple that with the intrinsic reliability and stability of transistors as compared to tubes (such as IOTs), and the latest generation of digital TV transmitters is advancing the cause of both efficiency and reliability.

Of course, solid-state amplifiers achieve high power output by using many low-powered modules added together. This adds complexity and signal loss, as all those power modules are combined and cooled. On the other hand, most manufacturers let you pull out a single bad module—even liquid-cooled modules—as the transmitter hums along using the remaining modules.

Doherty amplifier technology has allowed solid-state television transmitters to reach one of the Holy Grails of TV broadcasting: a solid-state transmitter with efficiency similar to tube transmitters.

What will the next generation bring?