Determined only weeks ago, the cessation of American analog television transition will be delayed until June 12, 2009, as approved by the U.S. House of Representatives and Senate. President Obama's impending approval of this delay is a foregone conclusion; he was in favor of this postponement even before taking office. This means that wireless microphones, IFBs and wireless monitors ("Part 74" as defined by the FCC) will also benefit from the delay of the new white-space regulation.
I received a call from Chris Phillips, Sennheiser's market development manager for the Southeast region, as he was making the Nashville rounds to educate houses of worship and theaters about the upcoming FCC change to the wireless spectrum. I gladly set up time with him, and we were having coffee while my questions were answered in plain English. My goal here is to translate the pertinent details of that meeting to readers of Pro Audio Review.
The transition to digital TV opened up some very coveted frequencies in the UHF range above 698 MHz. These frequencies require less power to transmit over longer distances; as such, they are very desirable to telecom companies, hence the $19 billion bid by giant corporations such as Qualcomm, AT&T, and Verizon for rights of usage.
Where to Begin?
To make sure your wireless systems are ready for the transition, start by taking an inventory of all frequencies for wireless audio equipment in your facility. By law, all wireless equipment should have the transmitted frequency written directly on the device. Anything between 470 and 698 MHz (TV channels 14 to 51) in the UHF band is safe and may be used without any interference from the transition. The same goes for the VHF band, 174 to 216 MHz (TV channels 7-13), although the focus of this transition is specifically for the UHF band.
Anything operating at 700 MHz and above will need to be replaced. This 700 MHz-and-higher space is now slated for release on June 12, 2009, but the changeover does not mean an immediate demise for wireless equipment working above that range. There will be some extra time needed for manufacturers to develop products, have them approved to work in those wireless ranges, and for the infrastructure to be built to support these networks. Now that there is an additional four months before the transition is implemented, the time period before the 700 MHz-plus wireless spectrum is put to use could be much faster, although, at this time, that is pure speculation.
Rebates, Buy-Backs, and Buy-Now Specials
One important factor in transitioning now rather than later is the amount of time offered by manufacturers for special buy-back rebates. Most, if not all, wireless pro audio manufacturers have offered trade-in programs for old wireless systems within the affected frequency range. For example, after doing an inventory on our church campus, it turns out the four primary wireless systems in our Worship Center will be affected. In order to take advantage of the trade-in program with Shure, I have to send in the new systems' UPC labels, the original receipt from the old system, and the old system itself, all by May 31, 2009 (This deadline was based on the original February 17 changeover: about a 4-month window.) Naturally, it is in our best interest to make a move sooner than later. Visit your gear manufacturers' websites to find out about their unique offers.
Navigating A (Potential) Wireless Traffic Jam
Considering these changes, will your equipment be all alone in wireless bliss once you are within the accepted 470 MHz to 698 MHz range? Nope. However, it will have first priority over TVBDs (television band devices), formerly referred to as white-space devices mainly used for high-speed broadband access with a much wider range than the current networks available.
The FCC legislates TVBD frequency usage to avoid interference with wireless audio equipment. This will be handled in one of three ways (or in a combination of ways): via Spectrum Sensing, Database, and/or Adaptive Power methodologies. First is Spectrum Sensing: the TVBD will scan the area for any other wireless device operating on those frequencies. If there is, the TVBD will be required to move to another, or cease transmission. Second is Database: there has been a proposal of a national geo-location database where wireless microphone users register their location and frequencies in use. The TVDB will then scan that database to see what frequencies are not in use and move to one of the available frequencies. Third is Adaptive Power: in this methodology, TVBDs will be required to utilize adaptive power and when they sense another device working within the frequency, their power will immediately decrease, preventing interference. No method listed above is set in stone, and as of this writing, there are no TVBDs available on the market. However, these devices could start making their way on the shelves as soon as late 2009.
Dan Wothke is media director at Belmont Church in Nashville, and he welcomes your comments firstname.lastname@example.org.