This is coming a few weeks after the fact, and some of you may already be aware of this but it's important to note that on November 18, 2008, the FCC finally released it's official ruling on what had been called White Space Devices (WSDs). They are now called TVBDs (TV Band Devices). While there's no shortage of anxiety regarding these devices, at least we now know what we're up against. Here is a summary of what we now know, and some thoughts on how it affects the church sound engineer.
There are two categories of TVBDs: Fixed and Personal/Portable. Fixed devices are permitted to operate in TV channels 2-51 (except 3, 4, and 37) at a maximum radiated power of 4W. Personal/Portable devices are permitted only in channels 21-51 at a maximum power of 100 mW (or 40 mW if operating adjacent to a TV station).
The rules stipulate that licensed wireless mics take priority over TVBDs, however there has yet to be any clarification on how a wireless mic user might get licensed. The TVBDs are supposed to use spectrum sensing technology to avoid wireless mics and TV stations, and until they can provide proof of performance that they can reliably avoid wireless mics and avoid causing interference, they must use a geolocation database to avoid permanent installations.
In 13 major markets, there will also be 2 TV channels reserved for wireless mic use. Those channels will be the first two open channels above and below channel 37.
So the good news is that just about anywhere in the country, we should be able to find at least 2 open channels to operate at least 16 wireless systems (8 per TV channel). I say should because there are still a lot of questions about how the geolocation database will work, and how well spectrum sensing will actually play out.
The fixed (and higher power) devices will be a known quantity, and we can frequency coordinate around them like we do with TV stations now. The bad news is that there will be any number of them coming online for the foreseeable future, and we might not know when and where they pop up. And with the portable units being banned from channels below 21, we at least have that part of the spectrum relatively free from roaming, variable interference.
No matter how it all turns out eventually, the fact is, our wireless spectrum is shrinking, and we need to start taking steps to reduce our dependance on them. The bottom line is that there will be increasing competition for the airwaves, and since we don't have nearly the budgets Google and Microsoft do, we'll won't win the battle.
I've been saying it for many months, and will continue to do so: If it doesn't need to be wireless, make it wired. You'll save yourself a lot of headaches (not to mention money and get better sound!).
Thanks to Sennheiser for their information on the ruling.