Frequency coordinator, wireless system designer, consultant, and entrepreneur James Stoffo is one of the most respected leaders working in RF today. The founder of Professional Wireless Systems and co-founder of Radio Active Designs, Stoffo, has over the last several decades, worked repeatedly for many of the world’s highest-profile award shows and sporting events, even writing the RF Coordination and Procedures manual relied upon by the Olympic Committee. We caught up with Stoffo recently to learn more about his work and tap his insights into deploying wireless audio.

How did you begin your work in RF?

My Italian grandfather had a wireless lab in his basement in Brooklyn and was a fan of Marconi. When I was about six years old, he shocked me with electricity and was rather amused at my reaction. I was instantly hooked and wanted to learn what this form of energy was. When I was 18 years old I became a radio surveillance specialist on an attack submarine for six years during the Cold War analyzing radio waves and determining threat potential to inform the captain. I was also the electronic technician for all repairs of communications and radar on the sub.

Left: Stoffo's Grandfather, Anthony Buzzanca, circa 1969, Brooklyn New York

Right: Electronics Technician 2nd Class Submarine Service Diver James Stoffo

For how many events have you covered RF?

A lot! Sixteen Super Bowls, a bunch of Latin and American Grammy and Billboard music award shows, Soul Train and Source Awards, Country Music Awards for many years, Kennedy Center Honors, several hundred Microsoft corporate meetings over the last 22 years, RF coordinator for the World Cup in 1992, 10 NBA All Star and Finals games, 20 Rose Bowl and College BCS games, and the Society of Broadcast Engineers from 1992 through 2005.

I also authored the RF Coordination and Procedures manual for the Olympic Committee, used as the blueprint for RF operations at every Games. I also designed the wireless for most of the Cirque du Soleil shows in Vegas and Disney World in Orlando.

James in RF land at the 2009 Latin Grammy Awards

How far in advance do you start working on particular projects?

Depending on the size of the event, I may begin the RF sweep and coordination two months in advance. Generally, at least several weeks of interfacing with the wireless audio supplier.

When preparing for a job in another location, how do you go about obtaining an RF scan of the environment?

I contact one of my many friends and colleagues that specialize in RF to go do an on-site RF sweep for me. Sometimes they require payment but usually not. We do a lot of favors for each other as it is a very small and specialized group of individuals, whom I am thrilled to call my friends. Professional Wireless Systems IAS software also has a function to find DTV in the FCC database and update a list for most cities.

What is your process for RF coordination? Do you like to tackle any specific type of device (wireless mics, comms, in-ears) before moving on to the next?

I always begin with an RF spectrum band plan based on the equipment being supplied from the wireless audio vendor. Then I coordinate the equipment that has the least frequency agility first. In general, these are usually the wireless in-ear monitors.

How much of your job is preplanning vs. overcoming issues on the fly?

Generally, a full day to two days is spent preplanning with the audio vendor and performing the actual coordination. Issues on the fly are generally gear shortages, broken equipment, interference and getting your RF rig wired to match the patch list from the A1 (audio boss).

What is your go-to analyzer and why?

I have several. My primary is a Rohde and Schwarz RF spectrum analyzer with a tracking generator so that I can check RF coaxial cabling before it is run to the antennas. This is then connected to my wireless receiver splitter so that I can see what the receivers are seeing. I also have a TTI portable spectrum analyzer to hunt down interference. It is light, handheld and tremendously accurate. I also have an RF Explorer because people ask me about it and it was fairly inexpensive. I do not use it often, but it is a good backup if I have assistants.

Left: Rohde and Schwarz RF spectrum analyzer

(photo credit: rohde-schwarz.com)

Right: RF Venue spectum analyzer

(photo credit: rfvenue.com)

When heading to a jobsite, what are some of the items in your toolkit that you couldn't live without?

I use many PWS accessories including RF band pass filters, passive RF splitters/combiners RF amplifiers and helical antennas.

Do you have any opinions of traditional RF vs. digital wireless systems?

Generally speaking, wireless audio transmission requires a certain amount of processing to package and deliver the audio from the transmitter to the receiver. This is done differently in both digital and analog systems.

Digital systems tend to operate more efficiently in less bandwidth and color the audio with fewer artifacts as RF signal degrades but are more susceptible to unexpected dropouts. In an Analog wireless system, the audio component is processed differently but can produce relatively comparable results to a digital system, depending on the application.

Additionally, as the RF signal degrades in an analog system, audio quality may be reduced but is less susceptible to total dropouts because there is no binary on/off element like a digital system. One can hear the interference and change radio frequencies before show time thereby avoiding unexpected dropouts or noise-up issues.

The application and deployment of wireless devices, as well as the available spectrum, should be considered when choosing analog vs. digital systems.

How would you describe the audio quality of the A-T 5000 Series?

I am thrilled with the audio and RF performance of the 5000 Series and have used them on all of my latest music award shows. The frequency agility and smart cover over the power switch keep me confident when the transmitter is out with the artist or host. I don’t have to worry about them, and when you are using 72 wireless microphones, I’ll take anything that will help me worry less.

Audio-Technica 5000 Series Wireless System

How does the RF environment vary in dress rehearsal vs. a packed venue?

Human bodies are meat sacks that are really good at absorbing RF. I find that when the audience loads in it can reduce the range of wireless microphones, and especially in-ear monitors, because any reflections between the transmitters and receivers are lost. At one Country Music Awards show, one of the artists’ in-ears were continuously dropping out throughout the course of the entire performance. They worked fine during rehearsals. I attributed this to the audience absorption of RF.

What advice do you have for someone doing RF coordination on a budget?

Download free or economically priced coordination software and use the wireless receivers as your spectrum analyzer. If you see RF lights on the receiver, you know that there is interference on that frequency. If possible, purchase an inexpensive analyzer such as an RF Explorer or one of those new tinySA mini analyzers – pretty accurate for $70.00.

What are some of the biggest mistakes you see when consulting on RF issues?

Too much unfiltered gain in the active receiver antenna system. The use of antennas that have RF amplifiers already connected to them. Too high of an RF power setting on the transmitters. These things raise the RF noise floor, reducing range and audio quality. The secret to successful RF operations is to maximize your RF signal-to-noise ratio. Use just the amount of power that you need for the coverage area and not a dB more.

What challenges do you see for RF audio in the future?

The biggest challenges will be the FCC continuing to auction off radio spectrum, leaving the wireless microphone and intercom community with less and less to work with. In addition to that, technology giants wish to take over spectrum for IoT devices. It is possible that we may end up with only one TV channel in every city. Not nearly enough to do a show of any size.

Throughout your career, what was your most challenging RF deployment?

Super Bowls were always a challenge because you had to coordinate with so many other users in such a small area and there was a lot of distance between the transmitters on the field and my position on the sidelines. That distance also had a very high RF noise floor. On multiple occasions, we would time-share frequencies. During the national anthem, certain coach comms had to remain off. Then right after the anthem, we would kill all of the music wireless and the game equipment would turn back on. Always a risky operation. In addition to that, it is all done live with no rehearsal. Let’s just say that Super Bowl Sunday is when I did the most praying.

From Left to Right: Jason Eskew, Deb Munini, James Stoffo, Carmine Stoffo, Mike Parker

Coordinating RF at Super Bowl XXXIX.

Look close and you'll see James' daughter, Elise Stoffo

saving the day and pointing a helical antenna at Carrie Underwood

during the National anthem at Super Bowl XLIV.

3 generations of Stoffos working RF for Super Bowl XLIV.

From Left to Right: Carmine, James, Elise

What has been the most enjoyable or impactful show that you have coordinated RF for?

Kennedy Center Honors. The show had a record-breaking number of transmitters, including multiple body-packs, wig microphones, and music handhelds. But I was proud and honored to have done it. Top-shelf audio crew. Great performances by the best-known names in entertainment.

To learn more about James Stoffo and Radio Active Designs, be sure to check out their website at https://radioactiverf.com/.

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