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Decision 2008 – White Space Disaster for Wireless Mics

by Erik Geiger on November 13, 2008

Last Tuesday, while many of us were casting our votes in the presidential election, the Federal Communications Commission (FCC) was making a landmark decision of its own. On their private ballot was a proposal to open the so-called “TV White Spaces” of the frequency spectrum for expanded use. And on November 4th, the proposal passed. Sounds all fine and good, right? Well, maybe not. If the FCC’s current plan goes through, it will lead to a crossroads for the wireless microphone industry and for AV designers.

The FCC forced Broadcasters to vacate the UHF spectrum so digital television can become a reality for every American household by February 17th, 2009.  As a result, it leaves a sizable part of the UHF spectrum open for use by “new technology” or “White Space Devices” (WSDs). The FCC has long viewed this spectrum (approximately 500 MHz to 700 MHz) as a prime way to deliver wireless broadband internet to rural areas, and this part of the frequency spectrum is well adapted to that purpose. The problem is that wireless microphones (like the ones used in every church, school, and auditorium) have been allowed by the FCC to use this frequency space for the past several decades.

Flash back to October 15, 2008… The FCC received a report on the viability of White Space Technology. The summary of the report indicated that, in the eyes of the FCC, the burden for proof-of-concept had been met. That is, opening the 500 – 700MHz frequency range for new technology and WSDs would be a realistic option. You can read the executive summary here:

http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-08-2243A2.pdf

The FCC then drafted a proposal to “re-task” the white space frequency areas for use by devices that would transmit anywhere in the available spectrum. While the summary indicates that the concept works, the 400-page report explains that there are significant issues with the technology, and that the devices tested do not do a good job of sensing when other technology (like wireless microphones) are using the same channels. In their testing, the new WSDs actually interfered with wireless mics in several circumstances.

The problem with the FCC’s Nov 4th decision is that it failed to clarify how much of the UHF spectrum would be re-tasked for WSDs and how much (if any) would remain available for wireless mics. Without further clarification, this could lead to some serious real-world implications.

As it stands right now, the decision complicates audio system engineering for AV designers like us at Acoustics By Design. Even worse, it muddies the waters for wireless microphone designers and manufacturers. Will UHF wireless mics become illegal? Will they become unreliable? The clock is ticking for every church, school, company, and organization that owns, or is thinking of purchasing, a UHF wireless microphone (the vast majority of all wireless mics currently in use). If the FCC doesn’t take action to clarify its regulations, it could lead to a real white space disaster for wireless microphones, and these devices could become nothing more than “white elephants”.

Erik Geiger

Erik Geiger

Erik Geiger, CTS-D, has designed and consulted on audio, video, and technical systems for over 20 years. He has served as an Audiovisual discipline leader and project manager, and carries a wealth of technical system consulting and design experience. Erik brings the heart of a teacher to every project, helping clients and end-users to understand a rapidly changing environment.

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KrisBelucci June 1, 2009 at 11:24 pm

Hi, good post. I have been wondering about this issue,so thanks for posting.

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