Some churches will have to stop using their present wireless microphones because the spectrum those microphones operate in has been sold by the Federal Communications Commission, according to an article in Your Church, an online publication of Christianity Today.
Microphones that operate in the 700 MHz band (698–806 MHz) cannot be used after June 12, says the FCC, which auctioned off the rights to that band in 2008 to (among others) Verizon and AT&T. Some emergency service providers also operate in that band, says the FCC. After June 12 all other users are subject to fines and will likely suffer interference from the new traffic, and may themselves cause interference, according to the article. The 700 band was formerly between the frequencies used by television stations. With the transition to digital television last June 12 the 700 band began to be used by public safety entities and commercial providers of wireless services.
Another article, by the FCC, is here. The FCC estimates that 25 percent of wireless mics operate in the 700 spectrum. A list of the affected devices, compiled by the FCC, can be found here. You can also call the FCC’s Consumer Center at 1-888-225-5322 (voice) and 1-888-835-5322 (TTY) for more information. The FCC says a small portion of affected microphones can be retuned to another frequency, but most cannot.