SVG Summit 2015: Wireless Audio Users Look Forward
At the SVG Summit on Dec. 14, Jacquelynn A. Green, Vice President of R&D/Engineering at Audio-Technica, joined Kevin Parrish, NBC Universal, Senior RF Engineer, Network News Field Operations; Henry Cohen Senior RF Designer at CP Communications; and Jeff Willis, outgoing Coordinating Technical Manager at ESPN, in parsing possible outcomes of the upcoming FCC RF spectrum reallocation process.
Green pointed out that while the spectrum auction, scheduled to commence in March 29, 2016 is intended to sell off the 600-MHz frequency range, “If it proves very successful it could reach into the upper ranges of the 500-MHz range.”
Noting that the last auction spread over approximately two months, she added that this iteration of the process and subsequent channel repacking analysis will take several weeks more until channel assignments are published. “So sometime in summer of 2016 is when will know more about how much spectrum is lost and know more about what frequencies we might be able to use. The FCC should issue the channel reassignments in fall of 2016” she said.
At that point, a 39-month period will commence during which wireless users of that spectrum will begin to vacate it. However, users must vacate immediately when entities that acquired spectrum at auction begin use of it. This may take place as quickly as six months post re-assignment, especially in major market areas. Some wireless-microphone operation will still be allowed in possible vacant channels, the guard bands, and the 11MHz duplex gap (with some technical restrictions in that gap). However, Green stated, “We won’t know where this operation will be possible until after the channel re-assignment.”
Meanwhile, wireless equipment manufacturers will be working on systems to utilize remaining spectrum. However, FCC mandates also stipulate that it will issue no new equipment type approvals in affected spectrum nine months post re-assignment. Furthermore, there is to be no sale or marketing of wireless mics in affected spectrum 18 months post re-assignment or 33 months after the rule-publish date. In addition, power levels inside the duplex gap will be severely curtailed — 20 milliwatts, down from as much as 250 mW in the past, which will limit range. Availability in the 900-MHz band will be increased, to help alleviate overcrowding in lower spectra, although the quality of that spectrum was questioned by panelists.
“We gained some flexibility,” Green acknowledged, “but we are clearly losing some spectrum.” Furthermore, she cautioned, the FCC is required to reallocate 120 MHz in the broadcast TV bands. If this auction does not go well and that goal isn’t met, there is a possible need for additional auctions to meet this requirement. In addition, if the repacking process runs into roadblocks in certain market areas, there may be impairments and some of the duplex gap spectrum may have to be reallocated to television stations.
Adding to the complexity of the post-auction situation is the fact that outcomes will vary by geography, and managing the changed RF landscape will be new ground for many. As Roger Charlesworth, executive director of the DTV Audio Group, pointed out, “The Today Show is right next to Broadway’s theaters — there’s over 600 channels of wireless right there. In New York we’re used to that kind of tightness, but smaller markets may not have the experience with that level of [frequency] coordination.”
Kevin Parrish added that the big city scenario would regularly be complicated by the unpredictability of ENG crews, noting that wireless would “require a traffic cop.”
CP’s Henry Cohen says that while the crews in the trenches have already begun wrestling with the changes that reallocation will spawn, C-level management at broadcasters will have to get strategic about it.
“The mindset that changes are coming has to start with upper management,” he said. Noting how available spectrum will be scattered, he added, “We will have to inventory a lot more equipment because there are no products that are frequency-agile enough to span that kind of fragmented spectrum. We have to plan budget and engineering considerations now, so we can move quickly to buy new equipment as it becomes available. There will be equipment from many more disparate brands on the trucks, depending upon where it has to go. Support will need to come from the manufacturers.”
Green did have some words of encouragement. She noted that the technology to use the 2.4-GHz range is mature. In addition, there are tools that can leverage ultra wideband (UWB) ,which transmits by generating radio energy at specific time intervals and occupying a large bandwidth, versus conventional RF systems that transmit information by varying the power level, frequency, and/or phase of a sinusoidal wave. There are other possible frequency ranges that can be utilized, including in ranges that mobile devices already occupy.
“The only reason we have what we do have is because we banded together,” she said in concluding remarks. “Manufacturers, broadcasters — we have to approach this collectively.”