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FCC R&O Puts Squeeze On Pro Audio RF

Wireless audio equipment operators and coordinators could face an increasingly tougher time finding usable frequency spectrum over the next three years as a result of a vote by the Federal Communications Commission on May 15.

Wireless audio equipment operators and coordinators could face an increasingly tougher time finding usable frequency spectrum over the next three years as a result of a vote by the Federal Communications Commission on May 15. The Report and Order (R&O) setting out the rules for the FCC’s Broadcast Television Spectrum Incentive Auction essentially forces wireless microphone, IEM and comms operators out of the 600 MHz UHF band and also snatches away the 12 MHz of spectrum—two TV channels—currently set aside for their exclusive use.

The R&O recognizes the “many important benefits” provided by wireless mics but notes that proceedings to identify alternative spectrum “outside of the television bands” will not begin for several more months. The rules only permit exclusive licensed operation by broadcast and cable entities—ENG crews—and in only 4 MHz of the 11 MHz-wide duplex gap separating the proposed uplink and downlink spectrum.

The R&O does permit operation in the guard bands between frequency blocks and in what the rules describe as “one naturally occurring white space channel in the remaining TV band in each area.” Operation is also permitted on channel 37, currently reserved for radio astronomy and medical telemetry, “at locations where it is not in use by channel 37 incumbents, subject to the development of technical rules to prevent harmful interference to the incumbents.”

But operation in the guard bands and channel 37 is open to all unlicensed users. That means that pro audio operators will be competing for bandwidth, with no protections in place, against consumer television band devices (TVBDs) or so-called whitespace devices.

Television stations relinquishing spectrum for auction to the telecommunications companies will have three years after the three-month filing deadline to transition to their new channels in the repacked spectrum, which means that RF mic users could potentially continue to operate in the 600 MHz band for the next 39 months. But stations could also move as soon as practicable and the new telecom services could come online before the deadline, too.

“What’s clear is that it’s a matter of physics,” says Karl Winkler, director of business development at Lectrosonics. “The reason everybody wants the spectrum is that it’s a perfect combination of good propagation with practical antenna size.”

According to Mark Brunner, senior director of global brand management at Shure, who has long been at the forefront of interactions between the pro audio industry and the FCC, “The outcome of all of this really has been the stark admission that the UHF band doesn’t contain enough spectrum to hold all of the professional wireless applications going forward. The commission will really need to seriously be looking at other spectrum that we may be able to use on a shared basis with other services to meet the needs of large events.”

Roger Charlesworth, executive director, DTV Audio Group, observes that even the current exclusive two-channel chunk is insufficient for large-scale sports and entertainment events, which routinely use 100 to 150 wireless frequencies, or about 10 TV channels. “Theoretically, there will be one ‘naturally occurring channel’ available after the channel repack, but I think that’s a fantasy,” he says.

If there is a silver lining, it is that eligibility for Part 74 licensing has been expanded to include professional sound companies and venues that routinely use at least 50 wireless mics. License holders will enjoy protection from unlicensed TVBDs through the TV bands database registration system set up following the transition to digital television in 2010.

The expansion of Part 74 eligibility is good news for professional content creators, such as film and TV producers, says Jackie Green, VP of R&D/engineering with Audio-Technica. “That content is one of the nation’s largest exports. I don’t think that anyone wants to shut that off.”

Mic manufacturers will undoubtedly now be redoubling their efforts to develop products for professional use in other frequency bands. But there are tradeoffs in terms of the technology challenges at higher frequencies and there are unlicensed incumbents in many swaths of the usable spectrum.

“The trouble is that what we’re going to have to do is employ every possible solution, because it’s hundreds and hundreds of channels every day, everywhere,” says Green. “And there is no one band that’s going to field all that spectrum.”

“We’ve tried to encourage the commission to identify any spectrum that exists below 2 GHz,” says Brunner. “The reason is pretty obvious— the technologies that we’ve developed in the UHF band can more easily be adapted to the next step up, which would be 1 to 2 GHz.”

Although the industry moved from VHF to UHF many years ago, he adds, “We also asked them to look at harmonizing some of the rules that exist in VHF for higher power operation there.”