[ Reprinted with permission from the August 08 NSCA Building Connections newsletter ]
Wireless microphone users have heard the horror stories. At worst, reports say no system will work after the transition to digital television (DTV) in February 2009. Others say systems will suffer from restricted use, limited bandwidth and flagging performance.
As we draw closer to the transition, it's time to set the record straight. Most people have heard only half of the story, and that half is often wrong.
Many wireless microphone systems operate within UHF bandwidths. Some speculate there will be no UHF band allowed for wireless microphones. However, while the UHF television band may become more crowded, it is not going away. It has been and will continue to be the largest and best spectrum for wireless microphone users.
The DTV Transition
Currently, the Federal Communications Commission (FCC) is reorganizing the UHF television band due to the transition from analog to digital television broadcasting. DTV stations will occupy a smaller section of the UHF spectrum (470-698 MHz) than currently allocated. The remaining spectrum (698-806 MHz) is divided into blocks, some of which have been, or will be, auctioned to companies for new nationwide wireless services; other blocks are reserved for public safety communications.
Despite the DTV stations comprising a smaller piece of the spectrum, there will still be unoccupied channels in every market. These "white spaces" are used by wireless devices, including microphones. The FCC is considering using white spaces for consumer wireless broadband Internet service.
What it Means for You
The scale and complexity of this project has generated confusion among wireless microphone users, resellers and even some manufacturers. Some of the rumors are dispelled below.
The white spaces are being auctioned false.
The White Spaces will not be sold to Google, Microsoft or anyone else.
Wireless microphones will stop working the morning after the DTV transition false.
Consumer devices permitted in the white spaces must include circuitry and software to detect and avoid TV broadcasts and wireless microphone signals. The FCC is currently testing this avoidance technology, and is unlikely to authorize new devices unless they adhere to these rigid rules and their performance is verified under real-world conditions.
Moving wireless microphones to other frequency bands before February eliminates the risk of interference false.
Although the 902-928 Megahertz and 2.4 Gigahertz ranges have been represented as spectrum lifeboats, these "boats" have holes in them. Even considering new, unlicensed devices post-2009, core UHF TV bands still have more space available than 902 MHz and 2.4 GHz bands, which translates into more channels for the user. Additionally, interference-free, high-quality audio is even more challenging in these bands where wireless microphones compete with other signals such as Wi-Fi and Bluetooth.
The Bottom Line
While no one can definitively predict how new wireless devices might share the spectrum with wireless microphones, the FCC insists the transition will be smooth. So don't sell your wireless system just yet; the evidence coming in tells us if it works now it will also work later.