Tech Sessions Delve Into Digital

The NAB Radio Show is a place to see the latest processors, transmitters, console and other gear on the exhibit floor. It’s a good place to socialize with others in the industry, too.
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The NAB Radio Show is a place to see the latest processors, transmitters, console and other gear on the exhibit floor. It’s a good place to socialize with others in the industry, too.

But for the engineering community, Charlotte also will be a spot for an intensive education in the latest broadcast technology, in three days’ worth of technical workshops.

The workshops begin Wednesday, Sept. 26, with the Society of Broadcast Engineers’ Radio Engineering Forum. As larger broadcasters refine their HD Radio implementations and smaller stations prepare to make the jump into the digital world, this year’s forum has a strong focus on HD Radio and other digital technologies.

EPG and more

The morning begins with an “HD Radio Technology Update” from Raymond Miklius, vice president at Broadcast Electronics.

With the impending transition of HD Radio from experimental to full commercial status, Miklius says broadcasters will soon have new uses that go beyond just audio on their data stream.

“Leasing bits in the HD stream for anyone who wants to transport data will be an important use,” Miklius said.

Those customers can include billboard companies and other advertisers who need to do occasional “large object transfer” of data to displays in remote locations, as well as electronic program guide data and perhaps premium programming that makes use of the “conditional access” technology now being developed.

Before the data stream can get to customers, it has to successfully make its way from transmitter to antenna, and then out to receivers. Measuring those digital signals isn’t always as easy as using an old-fashioned field-strength meter or modulation monitor, though.

Tim Holt of Bird Electronic Corp. will discuss some of the new challenges of VSWR measurements in broadcast systems, followed by Ben Brinitzer, Clear Channel regional vice president of engineering, who will speak on “The Pitfalls and Procedures of HD Radio Measurements.”

Are you a DRB?

In a world where broadcast engineers need to know as much about codecs and network analyzers as they do about microphones and cart machines (and yes, there are still some of those out there), the SBE is unveiling a new certification program.

Ralph Hogan, chairman of the SBE’s DRB Specialist Certification Committee, and SBE President Chriss Scherer will discuss details of the Digital Radio Broadcast Specialist program to be formally unveiled later this fall at the SBE’s national meeting in Pittsburgh.

Later in the morning, two giants of the audio processing world will share the stage to discuss one of the stickiest issues of the digital transition: the need to change completely the way most engineers have thought about processing for decades. The session is “Audio Processing for HD Radio.”

“You now have two entirely different signal paths at most stations,” says Greg Ogonowski, vice president of new product development at Orban/CRL. “There’s one for analog processing with pre-emphasis, and one for digital without pre-emphasis.”

Ogonowski says the latter path can — and often does — feed multiple transmission sources, from HD Radio to Webcasts to satellite transmission.

He and co-presenter Frank Foti, president of Omnia Audio, agree that the HDC codec being used for HD Radio presents challenges. “It’s not the best codec, and not the worst,” Ogonowski said.

Foti says the increased emphasis on multicasting at lower bit rates on HD FM stations is making processors work harder.

“Dynamics processing needs to have some added functioning to condition audio to sound good at lower bit rates,” Foti said.

At any bit rate, though, Ogonowski said the move away from the pre-emphasis that’s been used in most forms of analog recording and transmission, from LPs to tape to FM broadcasting, opens up the opportunity for much cleaner high-frequency audio.

“To me it’s a big selling point,” he said.

That, in turn, means rethinking some aspects of studio design to make sure digital and analog transmission chains both get what they need for quality signals.

Ogonowski says avoiding digital audio compression at the studio end is a good place to start, in order to avoid creating artifacts further down the chain when the audio is compressed again for transmission.

The Wednesday sessions conclude with another aspect of the signal chain that can make or break the quality equation, as Kevin Campbell of APT discusses “STL Considerations for HD Radio.”

Keep safe from RF

On Thursday, Sept. 27, the engineering sessions turn to an issue that affects both digital and analog broadcasters of all types: RF safety.

As transmitter sites and neighborhoods grow ever closer, RF issues are cropping up in an increasing number of “NIMBY complaints,” while at the same time broadcasters are dealing with new RF concerns from digital transmitters at shared sites and ever-stricter federal regulations.

Richard Strickland, the founder of RF Safety Solutions and an RW contributor, will conduct an all-day “NAB RF Safety Course” in two sessions, covering the latest OSHA and FCC regulations, workplace hazards, the special considerations of AM stations and the most recent FCC enforcement activities.

Meet your transmitter!

While the Wednesday and Thursday sessions are intended primarily for engineers with at least some experience, the engineering session on Friday, Sept. 28 is designed in part for radio people who may only know the transmitter as “that thing out on the edge of town that breaks right at the worst possible moment.”

John Bisset, Broadcast Electronics’ Northeast regional sales manager and writer of RW’s popular Workbench column, says that in these days of staffing cutbacks, it’s important for even non-technical types to have some understanding of what really goes on out there below the blinking lights.

His “AM/FM Transmitter Workshop & Breakfast” was a fixture for several years at the NAB Radio Show.

“This workshop started a number of years ago with a discussion of engineering for non-engineers,” Bisset said.

It returns this year by popular demand, “focused for people who want a good refresher course, or for studio engineers who are, frankly, scared of the transmitter site,” Bisset said.

With contract RF engineers increasingly stretched thin and in-house engineers focused on IT issues at the core of much of today’s technology, Bisset says it’s important for several people at any given station to have at least a basic understanding of some of the troubleshooting techniques that can help them get a station back on the air in a crisis.

“We’ll tell them what not to touch so they don’t kill themselves,” Bisset said. “It’s wise of NAB to not leave these guys hanging.”

“There’ll be a little on HD Radio as well,” Bisset says, for stations contemplating the digital future. The focus, however, will be on the good old analog sites that still represent the majority of broadcast facilities in small and medium markets.

One tip Bisset offers, even for those who can’t make it to Charlotte: Don’t be afraid to use transmitter manufacturers’ field-service hotlines. He says transmitter makers build the price of that service into their products’ cost, so there’s no reason to be hesitant to call for help when there’s a crisis.

Attendees will receive a take-home workbook and breakfast, both sponsored by BE, but Bisset says representatives from most of the big transmitter manufacturers will be on hand to round out the session with a roundtable discussion of their products and some time to answer questions from the audience.

Also during the show, the National Radio Systems Committee will meet on Wednesday afternoon.

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