Once the digital transition (DTV) concludes on February 17, 2009, there will be yet another big change if the Federal Communications Commission has its way. Low-power auxiliary stations, including bases for wireless microphones, will be prohibited from broadcasting in the 700MHz band on TV channels 52 through 69. The FCC yesterday voted to propose the ban in a Notice of Proposed Rulemaking and Order.

The decision will "ensure that low power auxiliary operations do not cause harmful interference to new public safety and commercial wireless services in the band," the agency's news release says. Full-power TV broadcasters will vacate channels 52 through 69 after February 17, leaving the area for public safety agencies and the commercial wireless companies that bought licenses in this years' auction of the spectrum. The FCC presently authorizes low-power auxiliaries to broadcast at around 100 meters, and some of them transmit in the 700MHz range.

The Order also proposes that the agency block the manufacturing and sale of low-power auxiliary applications that operate in that area (actually, it's 698-806MHz, to be precise). And outfits currently approved to run wireless mics and other devices as such will lose that privilege after the last day of analog broadcasting for full power television stations.

The FCC says it is "proposing" these measures because it plans to ask for public comment on the moves. But the agency seems pretty certain about its decision—the vote was unanimous. The Commission also says that it will impose a freeze on new applications for low power auxiliary stations intended for operation in said 700MHz region after DTV Day.

At present 156 entities are licensed to run these sort of stations in the 700MHz zone. Most broadcast elsewhere as well. Only 30 operate solely in various notches along the 614-806MHz dial. The permits are available to AM/FM radio license owners, broadcast networks, cable systems operators, and movie/TV producers. But critics charge that the band region abounds with illegal users.

Unauthorized and ineligible

In July, a consortium of public interest groups warned the FCC that unlicensed wireless mic use in the area poses a threat that will become more pronounced after the DTV deadline. The Public Interest Spectrum Coalition's (PISC) petition estimates that between 500,000 to 1 million unauthorized wireless mic systems operate in the 700MHz channels, "creating pools of potential interference that could undermine the reliability of these new public safety and commercial wireless systems."

PISC, which includes Public Knowledge and the Media Access Project, threw the book at wireless mic manufacturers in comments filed with the FCC in July. Their filing called for an investigation of nine companies that they say "willfully and knowingly" market and sell wireless mics to "unauthorized users for ineligible purposes." The coalition wants the FCC to probe Shure and eight other alleged culprits for "deceptive advertising practices," and offer "amnesty" for unlicensed wireless mic users, as long as they relocate their operations elsewhere.

The PISC filing represents something of a counterpunch at wireless mic advocates who charge that allowing unlicensed broadband devices to tap into the "white space" TV bands will cause interference. The FCC's Notice says nothing about that issue, but asks for public comment on the various elements of the petition. They include the proposed investigation and creating a new "General Wireless Microphone Service" (GWMS) that will broadcast across vacant UHF channels below Channel 52 on a secondary basis and eventually operate on the 2020-2025MHz Band.

Obviously wireless mic companies, especially Shure, are watching this proceeding with interest. Shure Director Mark Brunner told Ars this morning that the company "plans to work closely with the FCC" during this rule-making, and discontinued the marketing and sale of wireless mic products in the 700MHz area in 2007.

PISC sent out a press release calling the FCC Notice a "welcome step." PISC also includes the Consumers Union, the National Hispanic Media Coalition, the Open Source Wireless Coalition, and U.S. PIRG, among other groups.

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