DTV Audio Group Grapples With Spectrum Loss

The DTV Audio Group may want to get an annual pass for Acela Express, the high-speed shuttle train that connects the Northeast corridor and Washington, DC. The group’s leaders have been racking up miles with visits to FCC offices as they seek ways to ameliorate the pain that further RF spectrum auctions are going to wreak on professional users of wireless microphones and other devices in key spectrum areas like UHF.

“We’re expecting that we may lose as much as 120 MHz of spectrum altogether, leaving perhaps just 13 television channels for professional users to share,” calculates Roger Charlesworth, the DTV Audio Group’s executive director.

Ongoing discussions with FCC officials, he explains, have been aimed at communicating the problems further losses in spectrum will create for professional wireless users, including sports broadcasters and producers of political events, such as conventions and presidential debates. But it’s also about looking for alternative solutions.

“We’re adding our voice to those who are calling for preservation and protection [for professional wireless users],” he says. “But we know that, no matter what happens, we’re going to lose some more spectrum, so we’re also exploring what other parts of spectrum professional users may be able to access in the future, such as expanding the licensing model so that all professional users are represented.”

The FCC plans to conduct a two-sided broadcast-incentive auction in mid 2015: a reverse auction to pay broadcasters to vacate their channels and a forward auction that will sell the airwaves to the highest bidder. That auction has already been delayed more than a year, in part over concerns about how more spectrum loss will impact professional commercial users of the affected bandwidth, which will include the 400- to 500-MHz range preferred by broadcasters for its reliability, clarity, and ability to penetrate obstacles. Consumer wireless service and product vendors will be the largest buyers of the auctioned spectrum.

The DTV Audio Group’s constituency encompasses a wide swath of those professional users: manufacturers of wireless audio systems — microphones, IFB, intercom systems — including Sennheiser, Shure, Audio-Technica, and Lectrosonics; sports and news divisions of several major television networks; and frequency-coordination vendors, such as CP Communications, Broadcom, and BSI.

Both Broadcom and BSI work closely with producers of sports broadcasts and other live events heavily dependent on wireless audio systems. They have been talking directly with the FCC’s Office of Engineering & Technology and its Spectrum Auction Task Force.

Discussion topics include other areas of RF spectrum, including bandwidth as high as the 10 GHz range, that may be able to be conformed to the needs of various constituents, including the Broadway and touring theatrical shows that Charlesworth says need to be included in the agency’s considerations.

Long term, it’s becoming apparent that all of the UHF portion of the available RF spectrum will ultimately disappear: the FCC’s authority to auction spectrum extends through the end of 2020, and the scheduled 2015 auction will not be the last one.

Charlesworth says it’s inevitable that shared spectrum will be a major technical model going forward but many questions remain about how it will be implemented: “It’s becoming clear that large-scale broadcasters are going to have to be prepared to use little chunks of bandwidth from all over the spectrum in the future.”

He notes that the DTV Group’s constituency recognizes the dynamics behind the RF auctions: consumer wireless applications are a juggernaut and involve the leading technology companies, such as Verizon and AT&T. The organization recognizes that “the increase in consumption of media via mobile broadband is of benefit to everyone,” he says, emphasizing that discussions with the FCC are not adversarial in nature.

Noting the approximately 1,000 frequencies used by the production of the Super Bowl on Feb. 2, he says these talks also have to put into stark relief what broadcasters and other professional-level stakeholders are facing with further loss of spectrum: “We have to drive that home.”

Of the White Spaces — the buffer spectrum between broadcast channels that was once a reliable refuge for professional wireless users and that gave a name to the beginnings of what has become a game-changing decade of auction reallocation — Charlesworth predicts, “Soon there may be no White Spaces left to argue about at all.”