The 600 MHz band has been sold at a profit by the FCC to cell phone type companies. So 700 MHZ has been illegal for mics for a few years, and in 2018 600MHz will also be illegal. This is in the USA, home of commercialism in government. There's more to the story but it is too depressing to go into. As a pro engineer I have four sets of WL mics, all fortunately in the 500 band...