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SBE: New Wireless Systems Need Frequency Coordination

Society cautions against "further disruption" of UHF incumbents

The Society of Broadcast Engineers wants to make sure that a new wireless mic technology, if allowed by the Federal Communications Commission, won’t cause spectrum havoc.

The SBE has submitted detailed comments about proposed changes to Part 74 rules that would allow the use of Wireless Multi-Channel Audio Systems in broadcast TV bands and other Part 74 bands on a licensed basis.

WMAS systems have been proposed by wireless mic manufacturers like Sennheiser and Shure, and the FCC has an notice of proposed rulemaking open, asking for comments about them.

The engineering society told the commission it is “not opposed to the use of WMAS technology in the subject allocations,” but it said the use of WMAS in existing wireless microphone and low-power auxiliary service allocations should be subject to coordination with SBE local market frequency coordinators.

It also said WMAS systems should be operated only on a non-interference basis to incumbent wireless mic technologies, especially at UHF, “so as to not reduce further the nominal, residual UHF spectrum available for current technology wireless microphones.”

SBE also said WMAS should not be viewed as a replacement for conventional narrowband systems.

“Finally, the commission should carefully test and evaluate the increase in the noise floor that might result from the overlay of WMAS on incumbent narrowband wireless mic operation, and the effect of any such noise floor increases on the latter facilities,” it wrote.

“Reportedly, WMAS has a greater potential for interference than does current narrowband wireless mic technology, and WMAS has not been shown to be compatible with the large deployment of narrowband wireless microphones.”

SBE said it endorses the FCC’s efforts to encourage spectrum efficiency in the “extremely limited BAS allocations” available for wireless mics and other auxiliary facilities. “However, SBE urges that the commission not view this proceeding as a sufficient response to the critical shortage in available spectrum for wireless microphones, especially in the UHF television bands.”

Its full filing goes into detail about the recent history of spectrum management affecting wireless microphones. [Read the filing.]

SBE concludes: “We are hopeful that the commission will recognize that the authorization of WMAS must be done carefully so as to not further disrupt incumbent narrowband wireless mic operation, especially at UHF, and that the commission should establish as a high priority to make further accommodation for continued UHF wireless microphone and LPAS operation … Moreover, the commission should require that all users of WMAS technology participate in the frequency coordination process established as a service to the industry by SBE prior to commencement of operation at any given location.”

As we reported yesterday, the National Association of Broadcasters gave cautious support to the proposed use of WMAS, calling on the FCC to allow it on a “secondary basis” with “prudent restrictions” on its operations.