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The 600 MHz Transition Has Begun

By Steve Harvey. If you are about to order a wireless microphone or in-ear system that operates in the 600 MHz band, you need to reconsider. And if you already have such a system specified in an upcoming project, it’s time to issue a change order.

If you are about to order a wireless microphone or in-ear system that operates in the 600 MHz band, you need to reconsider. And if you already have such a system specified in an upcoming project, it’s time to issue a change order.

On July 14, 2017, the Federal Communications Commission published an Order on Reconsideration and Further Notice of Proposed Rulemaking that revised and clarified its rules to promote more effective spectrum access for wireless microphone operations in the TV bands, the repurposed 600 MHz band and other frequency bands. While some of the rules apply more to manufacturers—addressing antenna connections, the prescribed out-of-band emissions (OOBE) standard and output power restrictions, for example—the main takeaway for operators is that the days of unlimited spectrum for unlimited numbers of wireless mics, in-ears and comms are over.

What the Order does not address is the speed with which the new licensees are beginning to move into the 600 MHz band. Wireless carriers—T-Mobile, Dish, Comcast and AT&T, specifically—acquired significant swaths of spectrum in the FCC’s Incentive Auction, which ended on April 13, 2017. The FCC’s multi-phase TV station repack plan requires all wireless mic operators to vacate the 600 MHz band within 39 months of the auction’s close. However, while that transition plan requires wireless mics operating in the new 600 MHz service band (617-652 MHz and 663-698 MHz) to vacate no later than July 13, 2020, it could be sooner.

Much sooner, it transpires. The FCC has already warned RF mic operators that they must cease operations in the 600 MHz service band if they could cause interference to the new spectrum licensees. What has taken everybody by surprise is that T-Mobile announced mid-July in its Q2 earnings statement that it plans to fire up its first 600 MHz sites this month (the locations of which are unknown at press time), and begin selling smartphones in range by Q4, with further aims to build out a 5G network in the spectrum space within the next two years.

The FCC permits the new licensees to displace “protected” low power TV and translator stations with just 120 days’ notice, and incumbents are already receiving notification letters from T-Mobile. Since wireless mic operators are not in the FCC’s “protected” class, they will receive no notification that a carrier is about to begin operations in their market.

It should also be noted that a TV channel is 6 MHz wide yet the carriers bought spectrum in 5 MHz chunks, creating overlaps. That means that large blocks may become unavailable to RF mic users as the transition progresses.

One word you may begin hearing is “densification.” Having been moved out of the 700 MHz band during the 2010 DTV transition and now being required to vacate the 600 MHz band, wireless audio equipment users can expect the 500 MHz band to be at least 20 percent more crowded, according to estimates.

But it’s not all bad news. The FCC did listen to mic manufacturers and advocacy groups such as the SVG’s DTV Audio Group and opened access to some additional spectrum, including portions of the 169-172 MHz band, the 900 MHz band, the 1435-1525 MHz band and the 7 GHz band.

The bottom line is, wireless microphone operators need to familiarize themselves with the current FCC rules. They also need to remain vigilant regarding the operations of new 600 MHz band licensees as well as progress of the repack transition in their markets.

Operators should plan to vacate the 600 MHz band as soon as possible and move to the alternate available frequencies. The FCC has set a sunset date that prohibits “the manufacture, import, sale, lease, offer for sale or lease, or shipment of wireless microphones or similar devices intended for use in the United States that operate on the 600 MHz service band frequencies…after October 13, 2018.”

Users’ existing equipment may operate from 470 MHz to 698 MHz; that gear will need to be modified to limit the upper boundary and to comply with all the new technical operating rules, such as OOBE. The Order restricts power output for licensed and unlicensed equipment operating—appropriately, subject to the Commission’s rules—in the duplex gap and guard bands to just 20mW, again, requiring modification to remain compliant.

Now and going forward, users will need to mix and match spectrum, technologies and systems appropriately to the sources, and make their equipment choices based on needs, not convenience. Gear used indoors may be different to that used outdoors. Use wires wherever possible. Assign multiple comms belt packs to a single frequency.

Above all, operators who meet the FCC’s criteria should get a license. Without licenses, they can not register in the databases for protection against white space devices and other equipment operating on their frequencies. The FCC’s Further Notice proposes to expand licensing eligibility for certain professional theater, music, performing arts or similar organizations that do not meet the current minimum threshold of “routinely using” 50 or more wireless mics.

This is not the end of the spectrum grab, however. Microsoft is pushing the FCC for dedicated frequencies in the TV channel white spaces to deliver wireless services to rural America. Dedicated white space frequency spectrum for mobile devices and wireless mics is an unsettled matter still before the Commission, with no decision deadline in sight.

Also, the MOBILE NOW Act currently before Congress requires the National Telecommunications and Information Administration and the FCC to make available at least 255 MHz of federal and non-federal spectrum below 6 GHz for mobile and fixed wireless broadband use by December 31, 2020.