A purely political fight, not a technical battle
Years ago, the FCC lost control of wireless microphone users, and now it’s time to clean up the resulting mess. There are two big problems. First, there are wireless mics that operate in the 700 MHz band that the FCC has reallocated for commercial and public safety use. Second, there are a large number of illegal users, such as churches and theaters, that don’t qualify for licenses. The FCC has proposed some short-term fixes, but they don’t seem enforceable.
There are many legal users of wireless mics. They include broadcasters, cable operators, motion picture producers, and companies that produce programming for broadcast and cable. ESPN, for example, is a major user of wireless mics at sports events. These folks get licenses under Part 74 of the FCC rules in a category called “low power auxiliary stations.” The mics have been allowed to use a number of frequency bands, including 54-72 MHz and 76-88 MHz (TV channels 2-6), 174-216 MHz (TV channels 7-13), and 470-608 MHz and 614-806 MHz (TV channels 14-69).
But since the cessation of analog TV broadcasting, only TV channels 2-51 are needed for off-air broadcasting, and channels 52-69 (698-806 MHz, called the “700 MHz band”) have either been allocated for public safety communications or auctioned, or are planned to be auctioned for commercial mobile communications service. So goal No. 1 is to get the wireless mics off of the 700 MHz band so they won’t interfere with the new 700 MHz users.
That part is relatively straightforward. The FCC has just released an order that requires wireless mics to stop using the 700 MHz band as of June 12, and it requires manufacturers to stop selling wireless mics that operate at 700 MHz. Shure and other wireless mic manufacturers have been offering trade-in and rebate plans to customers that have 700 MHz wireless mics.
Proponents of white space devices (WSDs) that are supposed to operate on an unlicensed basis on unused TV frequencies are not too happy about this because the wireless mics operate on the same TV frequencies as the WSDs. But unlicensed WSDs are required to protect the licensed wireless mic users, like ESPN, from interference. So moving the 700 MHz wireless mics down to the channel 14-51 frequencies will make it more difficult for the WSDs to find clear frequencies.
But what really steams the WSD proponents is the FCC’s proposed treatment of the illegal wireless mic users. There are an unknown number of entities (possibly as many as 400,000) that use wireless mics even though they are not eligible for a license. These include churches, schools, courthouses, theaters and entertainers like Dolly Parton. How did this happen? Well, the FCC leaves it up to the equipment purchaser to know and understand the FCC rules and to operate transmitters according to those rules. But there is no FCC rule that prohibits a retailer from selling a wireless mic to a school or church, in spite of license eligibility rules.
Anyway, in a “stroke of the pen,” the FCC has legalized these users, at least temporarily, by putting their wireless mics under FCC Part 15.
There are two significant differences between the rules for these heretofore illegal users and the licensed users. The formerly illegals will operate under FCC Part 15 as unlicensed users that are not protected from interference. This is unlike the licensed broadcasters, cable operators and programmers, which are protected from interference.
Second, the now-Part 15 wireless mics must operate at an output power of no more than 50 milliwatts. This is compared with the licensed mics that can have power levels up to 250 milliwatts. (Shure has claimed that the majority of wireless microphones operate with a power level between 10 and 50 milliwatts, but who really knows?)
And finally, these now-Part 15 mics must stop using the 700 MHz band in June.
But this is all temporary, because the FCC has started a new proceeding to decide what to do in the long term. One proposal on the table is to make entities at theaters, entertainment complexes, sporting arenas and religious facilities eligible for licenses (and interference protection). You can almost hear the screaming from Google, Microsoft and other WSD proponents.
Meanwhile, the FCC is struggling with both near-term and long-term enforcement issues. How to make sure that existing users stop using the 700 MHz band? How to make sure that existing users comply with the 50 milliwatt limit? How to make sure that in the future, retailers don’t sell high-powered devices to ineligible users (one proposal would require manufacturers and retailers to keep records of their customers)?
In summary, it’s a mess. The FCC has no idea how many illegal wireless mics it has just legalized. It hopes that they will vacate the 700 MHz band. It hopes that they will operate within the 50 milliwatt power limit.
This new proceeding will be played out as a purely political fight, not a technical battle. Who has more power in Washington these days, Silicon Valley or the churches and professional entertainers? Dolly Parton vs. Bill Gates. It will be fun to watch.