The much-discussed auction of the 600 MHz frequency band is happening in the U.S., and it may well affect present wireless systems as well as related issues such as frequency planning/coordination.
It’s important for everyone who works with creating the content that will stream on the mobile devices when the spectrum is cleared to understand the present situation and to be planning for the transition to different frequency bands.
Several leading pro audio wireless system manufacturers have taken the lead in working with the U.S. Federal Communications Commission (FCC) as well as other wireless stakeholders to insure that sufficient spectrum remains available for pro audio. They (and others) have also been highly involved in providing education on the coming changes and in developing products to meet future requirements.
Let’s take a look at the likely end results of the auction, the possible timeline of when the 600 MHz band will no longer be usable for wireless systems, alternative frequency bands, the benefits of licensed operation, new technologies that wireless manufacturers are developing, and what actions users can take to smooth the transition.
But first, note that the category of “wireless microphones,” per the FCC, covers a variety of wireless audio devices typically used in concert and event production, churches, public facilities, performing arts venues and even local night clubs. This equipment includes wireless handheld mics, headset or lavalier mics with bodypack transmitters, guitar transmitters, intercoms, in-ear monitors (IEM), and IFB systems used to cue and provide program feeds to on-air talent. Each uses a certain portion of RF spectrum to function.
The Process Is Underway
Officially called the Broadcast Incentive Auction, the 600 MHz spectrum is being repurposed from television broadcast to mobile broadband and similar telecom applications. Earlier this year, broadcasters were invited to provide a price for which they would be willing to give up the spectrum they occupy, and agree to either move to a less desirable band, share spectrum with other broadcasters, or cease broadcasting. This provided the pool of available spectrum for the telecom companies to bid for.
Initially, more than 4,000 “blocks” of spectrum throughout the U.S., consisting of paired 5 MHz bands for upstream and downstream broadband transmission, were offered. This spectrum spans 126 MHz and has an asking price of approximately $88 billion. Bidders include companies such as AT&T, Verizon, Comcast, and Dish Network. Purchasing the right to use this spectrum more or less involves a process of multiple bidding “rounds,” with each stage of bidding offering less spectrum for sale – and eventually concluding when the total amount bid is equivalent to the price that broadcasters had agreed to.
As of mid October of this year, the first stage had been completed, while the second stage offering 114 MHz just closed without meeting the target. Joe Ciaudelli, director of U.S. Spectrum Affairs at Sennheiser, states, “The worst-case scenarios didn’t come to fruition,” adding that he anticipates that the amount of spectrum up for auction will be less going forward, and that a third bidding stage and possibly more will be necessary.
Mark Brunner, senior director of Global Brand Management at Shure, notes that some industry observers expect the end result might be approximately 86 MHz of spectrum becoming cleared and unavailable for use by wireless microphones. “This is a better outcome for pro audio as far as more UHF spectrum remaining available,” he says, adding, “However, it may also change the size of the guard bands” which are potentially open for shared use. Karl Winkler, vice president of Sales & Service at Lectrosonics (and LSI author), concurs and suggests that, “The floor for new services will be the top of TV 37.”
Timing Issues
Once the auction is complete (it may extend into 2017), wireless microphones and related devices operating in the cleared bands will have 39 months to make the transition, after which their use in that spectrum is banned. During this time period, “Telecom services will be moving into their newly acquired space on a market-by-market basis,” according to Brunner. “This is what is challenging for wireless mic operators, in that the 600 MHz band spectrum that is auctioned will not all be declared off-limits at a consistent time; it will also vary market by market. The only requirement is that they don’t interfere with newly licensed services that come on the air.”
So during the transition, it will be necessary for users to use RF scanning hardware and software to conduct local environmental scans before setting channels in cleared spectrum. They will also need to consult the nationwide geo-location databases, which will reflect the new services commencing operations in those markets. Complying with cases of interference will continue to be done as it is currently, which is on a complaint-driven basis.
“I don’t want to sugar-coat things – the transition is not going to be easy,” Ciaudelli says. However, he points out that the broadening of licensing categories for larger users and opening new bands of spectrum are offsetting aspects of the 600 MHz clearing.
