White Space Impact on Wireless Audio
While the transition to digital television is a big story, there are smaller but no less important stories being pulled along in its wake. One of particular interest to AV pros is that of white space and its impact on wireless audio.
The issue over frequency sharing becomes more alarming when you take into consideration the compression of TV channels that will happen after February 17. UHF TV channels 52–69 will go away forever, with some channels re-assigned for use by public safety agencies and others auctioned off for new services, such as expanded cellular telephone frequencies. (Ironically, Qualcomm's MediaFLO mobile TV service will occupy the former UHF channel 55 nationwide, post-transition.)
That means the available spectrum for UHF wireless audio now cuts off just below 700 MHz, so things are going to get a bit more crowded as stations relocate back into the new, smaller UHF “core.” Amazingly, the FCC has not yet updated rules for wireless audio use of the former channels 52–69. Can it continue as before?
There is considerable pressure on the FCC these days to free up more RF spectrum for consumer electronics applications. Manufacturers want to sell more computer-centric products into the home in pursuit of the holy grail—a centrally located media hub that can serve up movies, TV shows, photos, and music to any computer, cell phone, or TV on demand.
The bandwidth requirements for such networks are considerable, particularly when streaming HD TV. And there are far more potential customers living in existing homes where pulling Ethernet cables would be a major nuisance and unwanted expense.
If anything, the FCC should err on the side of caution. We live in an age of cost-cutting and cheap, mass-produced electronics. In such an age, performance is often shortchanged in favor of affordability and operating convenience. As a long-time Extra Class amateur radio operator (KT2B) who's spent a little time operating on frequencies as low as 1.6 kHz and as high as 10 GHz, I just don't see how white space products, wireless microphones, and digital TV can coexist.
My solution? Have the FCC set aside some of the freed-up UHF spectrum (or other spectrum) exclusively for white space operation, and let CE manufacturers go crazy. If interference becomes an issue, it's limited to other white space devices, which should be using spread-spectrum communication anyway.
And leave the TV/wireless audio shared spectrum relationship alone. It's worked remarkably well for many years, and both parties have a vested interest in keeping it that way. Remember the old saw: If you fool with something long enough, you'll break it.
InfoComm Educator of the Year Pete Putman is a PRO AV contributing editor and president of ROAM Consulting in Doylestown, Pa.