Editor's Note: In our continuing series on broadcasting history, James O'Neal takes a look back at technology milestones that occurred in April. 

February: Looking Back at Broadcasting's First 100 Years
March: Broadcasting: The Way We Were

As we approach the 2022 NAB Show, let's take a look back on some of the past highlights of this indispensable part of the broadcasting scene.

It’s not possible to go back a full century as a starting point, as broadcasting didn’t really take off until 1922, and there was no show—or National Association of Broadcasters—until the following year. 

Sufficient documentation does exist, however, for examining details of the show held to commemorate the 10th anniversary of broadcastings emergence as a societal gamechanger and major industry. (And though it may come as a bit of a surprise, the NAB Show hasn’t always been held in April and in Las Vegas. Show dates have meandered throughout the calendar, and it wasn’t until 1975 that it got to Nevada.)

90 Years Ago – 1932
St. Louis hosted the three-day NAB Show, which got underway on Nov. 14—just in time for a heavy snowstorm. Harold A. LaFount, acting chair of the Federal Radio Commission opened proceedings with an address in which he urged unity within the broadcasting industry to face the problems confronting it and to keep American broadcasting “the best in the world.” 

The new NAB president, Alfred J. McCosker, vowed to lobby for longer-term station licenses, as renewals then were required every six months. Sessions addressed other issues faced by Depression-era broadcasters, including copyrights, exorbitant network line charges and license fees for record turntables. 

Engineering sessions included a presentation by Washington radio attorney Louis G. Caldwell, who urged a move to long wave broadcasting by U.S. broadcasters to help alleviate band congestion and provide better service. (Long wave broadcasting, while successful in Europe and other regions, never caught on in the United States.) 

Television was not on the agenda, even though RCA/NBC had been conducting tests on the new medium since 1929, and had recently established a transmitter site atop New York’s new Empire State Building for testing the feasibility of VHF spectrum for TV broadcasting. Despite the “hard times,” the show boasted a record attendance of nearly 400.

75 Years Ago – 1947
Television was unquestionably the focus of the Sept. 15-18, Atlantic City Show, with RCA’s exhibition of a 6-bay antenna stretching almost all the way to the 150-foot ceiling of the city’s convention hall. The antenna and a mobile truck also on display were destined for Baltimore’s WBAL-TV start-up after the show. 

The 1947 event registered the highest attendance ever, with nearly 2,600 attending sessions and viewing equipment exhibits. In addition to TV gear, exhibitors also showed off facsimile technology, which was being touted as a delivery mechanism to get daily newspapers into homes. (The top two MHz—106 to 108 MHz—of the “new” FM band was originally designated for facsimile transmission.)

50 Years Ago –1972
The April 9-12 Chicago NAB Show marked the event’s golden anniversary and also the 23rd time it was hosted by the “Windy City.” Engineering sessions featured presentations on a number of contemporary topics, including maximization of video chain and transmitter performance (dual-redundant TV transmitters were just coming into their own). 

There was also a “faceoff” of sorts between members of an FCC panel and station engineers. When asked about special training Commission field inspectors received on broadcast operations, the FCC rep’s answer was “none,” which raised a comment from a station engineer about this being obvious, as he’d had to instruct an inspector on proper use of a field strength meter. 

Out on the exhibits floor, Amperex was celebrating the recent delivery of its 20,000 Plumbicon camera pickup tube, RCA was showing off its new TK-44B Plumbicon studio camera and TK-28 telecine camera, which could be supplied with either vidicons or Plumbicons. Personnel at the Ampex booth stayed busy explaining the feature set of the company’s new 2-inch cassette VTR, the ACR-25 (and how it was superior to RCA’s TCR-100). 

25 Years Ago – 1997
The move to digital television was high on the agenda at the April 7-10 Las Vegas NAB Show. A line in the sand had been drawn for analog switch-off by 2002, and this was not sitting well with attendees—especially operators of smaller market stations—due to the high cost of making the transition and uncertainty about recouping expenses. 

A continuing debate over the best digital standard was also permeated the show, with cases being made for both 720p and 1980i. (Kodak, still a big player in TV production and broadcasting, advocated sticking with film until video standards “shook out.”) 

Transmitter manufacturers reported a lot of interest in new digital-capable units; however, most of this was from “tire kickers,” with sales orders not expected until the following year. While there were plenty of digital-ready transmitters, broadcasters wanting to move to high-power solid-state UHF models would have to wait. 

As one large transmitter company UHF products line executive explained things: “We are not ready to mass produce solid-state [UHF] DTV transmitters at this point. No one in this business is.”

BALTIMORE—Acrodyne Services has deployed a self-contained TV transmission solution designed to keep broadcasters on air while they replace or modify their existing transmitters.

The Mobile Acrodyne Transmitter (MAT), offering support for both ATSC 1.0 and 3.0 transmission, is a climate-controlled trailer with a one-rack, liquid-cooled Rohde & Schwarz THU9evo UHF 19kW transmitter with 12 amplifiers, a Dielectric tunable mask filter, patch-panel, test load plus pumps and separate heat exchangers for the transmitter and test load.

The UHF version of MAT has been deployed several times, and a VHF version is planned for deployment later in the year, Acrodyne Services said.

“Stations and TV groups are continuing to upgrade their broadcast infrastructures by replacing old transmitters,” said Acrodyne Services General Manager Andy Whiteside.

“There are low-power solutions and other workarounds, but none of them are ideal, especially for stations that have limited space or run into unexpected delays because of logistic and structural issues. MAT provides a clean, external and high-power solution that allows broadcasters to conduct business as usual,” he said.

Stations that rely on MAT need only supply AC power and an input signal from master control. Acrodyne provides a run of coaxial flex line to connect MAT’s output to the antenna to maintain regular broadcasting, Acrodyne Services said. 

MAT’s initial deployment was in June 2020 at WLFL/WRDC, the Sinclair Broadcast Group duopoly serving Raleigh-Durham, N.C.  At the time, Sinclair was replacing the stations’ transmitters—both in the same room—and installing a new filter for WRDC. (Acrodyne Services is a wholly owned subsidiary of Sinclair.)

“There just wasn’t enough room for all of that work,” said Rusty Mooney, Sinclair manager of TV transmission engineering. “You’d run out of wall space trying to keep one transmitter running while trying to build a new transmitter.”

With MAT parked outside the facility and transmitting, the old WRDC transmitter was removed. When the new WRDC transmitter was commissioned, MAT was quickly reconfigured to broadcast for WLFL while its transmitter was replaced.

MAT also was used January through March at Sinclair’s KDNL in St. Louis while the station completed extensive renovations and replaced its two-cabinet IOT transmitter, Acrodyne Services said.

The idea for a transmitter on wheels stems from the FCC repack of TV spectrum. In September 2020, WHKY, the Long Communications-owned independent station serving Charlotte, N.C., rented an early version of the mobile transmitter while updating its facility and installing a new transmitter, Acrodyne Services said. 

Once Sinclair has completed all of its repack projects, the broadcaster expects to replace its remaining IOT transmitters at about 20 of its stations with solid-state transmitters.

Dale Scherbring, Sinclair director of engineering for RF transmission, expects to use MAT at those locations and at the VHF-to-UHF conversions currently being considered. However, he said MAT can also be deployed for emergency or disaster situations, and the system can be operational within a day.

MAT will be available to all broadcasters subject to demand and availability, Acrodyne Services said. 

More information is available by emailing Acrodyne Services.

BALTIMORE—Broadcast industry consultant Kessler and Gehman Associates (KGA) is using Acrodyne Services’ Progira plan broadcast network planning software to help broadcasters develop their NextGen TV strategies, particularly to assist with single frequency network (SFN) planning,  Acrodyne announced.

“We purchased Progira plan for a variety of projects around spectrum planning and optimization, but there’s no question that the main scope is for ATSC 3.0,” said Ryan Wilhour, consulting engineer at KGA.

The planning tool is used around the world by consultants and broadcasters to design broadcast networks with optimum reception probability. Over the past few months, Acrodyne has experienced increased sales of the tool in the United States as broadcasters near the end of the TV spectrum repack and begin planning ATSC 3.0 deployments, the company said.

Many broadcasters are considering SFNs for 3.0 as a transmission model—a stark change from the high-power big stick approach employed for ATSC 1.0 transmission. Progira plan offers a sophisticated toolset for SFN planning and helps consultants plan networks with multiple transmitter sites designed to reinforce each other for consistent market-wide reception and interference avoidance, said Andy Whiteside, general manager of Acrodyne Services and president of Dielectric. The tool assists users in understanding reception conditions and network timing requirements for mobile users, he added.

“The main benefit [of Progira] is the amount of time we save in planning SFN sites,” said Wilhour. “The software interfaces with the FCC LMS database and exports studies to TV Study for final FCC presentation.

“It automatically defines the appropriate antenna patterns and network timings,” he said. “No longer must the broadcast consultancy pull in antenna patterns, apply them to contours one by one, and evaluate if they remain within allotted coverage areas.

“The software integrates seamlessly with ArcMap geographic information systems (GIS) as well, and allows me to very quickly generate contours and their population counts,” he added.

However, not all broadcasters are considering SFNs for 3.0 deployment; some will rely on their conventional tall tower. The Progira plan is appropriate for reception prediction of both approaches, said Whiteside.

To date, KGA has put the Progira plan to work on a variety of projects, including SFN planning in San Francisco to model potential reception plans for several UHF TV channels and to plan a studio-to-transmitter microwave path profile for an ATSC 1.0 broadcaster.

“There is no question that we are finding new business and making money by using this software,” said Wilhour. “We have one client that is looking at ATSC 3.0 SFN plans for all major markets, and they understand the requirement for accurate coverage models. We can start with the basic metric analysis and then provide very detailed theoretical data that will help them accelerate network buildouts, from identifying proper antenna patterns to gaining construction permits. This software opens up many new business opportunities,” said Wilhour.

More information is available on the Acrodyne Services website.

BALTIMORE—As the transition to ATSC 3.0 is just over the horizon, Acrodyne has announced the first sales of its Progira broadcast network planning software to U.S. customers. The Merrill Weiss Group and Marsand are among the first companies to acquire the software.

Featuring ATSC 3.0 and 1.0 options, the Progira software offers CRC-Predict and other propagation models, which are designed to predict true reception probabilities.

Acrodyne, a subsidiary of Sinclair Broadcast Group, became the exclusive distributor of Progira in September of 2016. 

BALTIMORE—Sinclair Broadcast Group subsidiary Acrodyne has come to terms with Progira to be the exclusive distributor of its broadcast and network planning and design tools in North America. This will include the PROGIRA plan software, as well as training and support.

“After working with PROGIRA plan software for the last year, it became clear to us that PROGIRA was dedicated to delivering a solution tailored for what is widely anticipated to be the next U.S. broadcast standard, ATSC 3.0,” said Andy Whiteside, general manager of Acrodyne Services and president of Dielectric.

Acrodyne and Dielectric plan to work with One Media 3.0 and use PROGIRA plan to build out a national footprint using ATSC 3.0, according to the company’s press release.