The Final Word on Wireless Mics

Heed the shutoff order starting June 12
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The uncertainty started as part of the digital television transition, when the FCC ordered analog TV stations to vacate the "700 MHz" band frequencies (698-806 MHz), which were formerly used for TV Channels 52 through 69. A "White Space allocation" plan called for these to be used by emergency radio and public safety operations as well as certain commercial mobile applications. Since many UHF wireless microphones also operated in this band, the initial rules called only for the cessation of manufacture, sales and distribution of 700 MHz wireless mics. Continued use of existing units was initially not addressed, and this led to two years of confusion on the part of many users.

by Wayne Cole

On January 15, the FCC issued two rules that constitute the final word on UHF wireless microphone use in the 700 MHz band. FCC 10-16 reiterated the ban on the manufacture, sale and distribution of wireless mics that operate in this band while DA 10-92 defines the "consumer alert" manufacturers must supply with wireless devices that operate outside this band. In particular, it defines what devices may be operated without a license, and most wireless mics fall into this category.

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Sennheiser's popular Evolution G3 wireless systems, available in a number of configurations, get high marks from users for sound quality and reliability. These rulings confirm that all 700 MHz wireless microphones must cease operations after June 12, 2010. Failure to do so could result in both civil and criminal penalties. Just from a safety standpoint you wouldn't want to be the one interfering with critical fire, safety, and police emergency radio services that now occupy the 700 MHz band. The consequences go beyond mere annoyance and could be life-threatening. So don't take a chance. As painful to the pocketbook as it might be, you need to heed the shutoff order.


Along with publication of these rules, the FCC also posted a list of wireless mics from the primary manufacturers that are affected by the ban. The list indicates by model number which units might be upgradable and which units cannot be modified to "legal" specs. Manufacturer Web sites also appear in this list that serve as a starting point for a search for rebate or re-banding programs that can help offset the cost of replacing legacy units.

For example, the ElectroVoice RE-2 UHF series can be modified to operate. While not easy to find there, the ElectroVoice Website indicates that Bosch Security Systems (current owner of EV and Telex wireless mic lines) offers both re-banding for certain EV and Telex units, and rebates for exchanges on new systems. Likewise, Lectrosonics offers exchange or modification on certain models made after February, 2004. In addition to certain listed WL-800 series units, Sony also offers new units in that series and in the UWP line that operate outside the restricted band.

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The various rebate, exchange or modification programs end between March 31, 2010, and September 20, 2010, depending on manufacturer. Some manufacturers, like Audio-Technica, offer smaller rebates for trade-ins of other manufacturers' equipment which can be a small help to those like Samson 700 MHz wireless mic users who have simply been abandoned by Samson. Finding these programs on the manufactures' Websites can be challenging. However, search terms like "700 MHz", "White Space" or "DTV Transition" will usually reveal the desired information.

Wireless devices that can be operated without a license are also restricted from using any active interference rejection technology. So before ordering any replacements or re-banding you should check the frequencies available in your area. Shure, Sennheiser, Audio-Technica, and other suppliers have online tools to help you determine the frequencies in your area where you should be able to operate with little or no interference. The Sennheiser USA Website has a particularly nice interface to the FCC TV broadcast frequency database which shows a Google map rendition of licensed broadcast users in your chosen radius about a U.S. city or ZIP code. Below the map, Sennheiser displays a table of frequencies that you can filter to show all, used, or available channels.

If you can't trade in or upgrade your older UHF wireless systems, the FCC's wireless mic website FAQs provides links to help you locate electronics recyclers in your area.


Another source of confusion for wireless mic users was figuring out whether or not they required a license to operate their mics. Even FCC officials I spoke with in January and April of 2009 were uncertain of the requirements for non-broadcast wireless mic users including churches, event and legal videographers. Apparently enough questions were raised during the process of vacating the 700 MHz band that the FCC decided to explicitly address unlicensed wireless microphone users.

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The consumer alert required by DA 10-92 clarifies that issue in simple terms: If your wireless transmitter emits 50 milliwatts or less of RF power, you do not need a license. Most individual wireless microphones operate at or below this limit. Also, if you operate multiple 50 mW wireless mic transmitters at the same time you might create overload/interference at short distances from the receiver. To deal with such issues, some makers, like Sony and Audio-Technica, allow the transmitters to be switched to 10 mW output, which works well at typical indoor venue distances.

Part 74 licensees must also stop using 700 MHz wireless mics. However, they can license another "legal" band to operate systems that may radiate more than 50 mW. Such licenses are restricted to broadcast radio, TV and cable operators. Most of us fall outside that limited community, and will likely only have ready access to sub-50 mW units, so licensing should no longer be a concern.


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