WASHINGTON, DC—On September 30, the Federal Communications Commission (FCC) released a Notice of Proposed Rulemaking (NPRM) putting forward amendments to Part 15 of its rules, affecting unlicensed wireless operations in the 600 MHz band. The FCC simultaneously released a second NPRM intended to promote wireless mic spectrum access at other frequencies as operators are transitioned out of the 600 MHz band to free up bandwidth for consumer broadband services.
The NPRMs relate to the FCC’s Incentive Auction, which encourages TV broadcasters to voluntarily give up some or all of their spectrum in exchange for incentive payments. According to the plan, those broadcasters will have three months to vacate their current spectrum. The repacked spectrum will be auctioned off to wireless providers. Broadcasters remaining on the air must transition to their reassigned channels within 39 months.
What this means is that wireless microphone (and in-ear and comms system) operators may be able to use the 600 MHz band for up to four more years. But a blog post on October 24 by Gary Epstein, the FCC’s incentive auction task force chairman, indicated that legal challenges to the plan by the NAB plus other complexities will now delay the auction (this is the second delay) until “early 2016,” extending that deadline slightly.
The NPRMs offer some clarity to the expected timeframe, acknowledges Jackie Green, Audio-Technica’s VP of R&D/engineering, but 39 months is the maximum time allowed for the transition. “There are shorter timeframes listed in there,” she says.
Mic manufacturers are particularly concerned about the FCC’s proposal regarding which wireless microphones may be legally operated after the transition. The Part 15 NPRM states, “[I]f a wireless microphone is certified to operate in any portion of the repurposed 600 MHz Band, we propose that it may no longer be marketed or operated after the specified cutoff dates, even if it could be tuned to operate outside the repurposed 600 MHz Band.”
“They’re saying, when this stuff goes live—when the 600 band is auctioned off and the new services get ready to fire up—your products and your users can’t use those new frequencies,” says Karl Winkler, director of business development at Lectrosonics. “But they also are proposing that we won’t be able to use any devices that are capable of tuning to these old frequencies.” However, he says, “They’re not guaranteeing that it’s going to be the same in every metro [area], although they’re saying that’s the idea.”
In lower tier markets, the spectrum might not be auctioned off, creating a situation where different bandwidth might be legally accessed in different areas. “So are we supposed to make products that are only for use in Cleveland? That’s completely nuts,” says Winkler.
That uncertainty also applies to the exact frequency spectrum that will be affected, says Mark Brunner, Shure’s senior director of global brand management. “This auction could run from 620 to 698; it could run below 600 if there are enough broadcasters willing to participate. That creates a little bit of a challenge not only for operators but manufacturers designing equipment. We need to know what the future TV band is going to look like before we can produce new SKUs that tune properly to the frequencies that will be legal.”
“The unfortunate truth is, they’re likely to do another auction after this,” says Joe Ciaudelli, spectrum affairs, Sennheiser USA. “If you look at the Incentive Auction Report and Order, they have all these different repacking scenarios, and the twelfth basically repurposes 144 MHz of spectrum. It’s my speculation that is their eventual long-term goal.”
The FCC proposes to eliminate the two channels currently reserved for wireless mic use, designating one channel—where possible—in each market where they can share bandwidth with whitespace devices. Licensed RF mic users will be able to use a 4 MHz sliver of the “duplex gap” and can share another 6 MHz of the guard bands with whitespace devices.
But as Ciaudelli points out, the duplex gap is “a buffer to protect two blocks so they don’t interfere with each other. So just by definition, it’s not clean, reliable spectrum.”
Licensed users—the FCC has extended eligibility to include anyone regularly using 50 RF mics—must register their events in the existing independent databases to receive protection from interference from whitespace devices. “Whitespace devices aren’t really testing it; there are no portable whitespace devices out there,” notes Green. “Truthfully, not that many wireless microphone people are entering their use, either. So there’s not currently an accurate view of what the database is really going to have to handle.”
“[The NPRM] bumps up the frequency with which whitespace devices are supposed to check in to the database,” adds Winkler. The devices will be expected to check in and avoid using the wireless mic’s registered channel within 30 minutes.
The FCC’s notice on alternative spectrum for wireless microphones offers more questions—a couple of pages of them, in fact—than answers. But that NPRM is something of a win, according to Brunner. “It reflects a lot of input that the wireless mic part of our community provided to the commission with regards to alternative bands. That’s a reflection of months and years of dialog on alternatives, all in one place, and that’s nice to see.”
Inevitably, says Green, “It’s going to change how people set wireless up, it’s going to change the equipment they have to use to accomplish the same results and the frequency bands of operation may change. All of us are trying to stick to UHF as much as we can, but there’s going to be a lot of innovation—technical solutions and product solutions.”