JetWash,
Wireless microphones typically operate on "locally unoccupied" UHF TV Channels at 470.0 thru 608.0 MHz.
As a result of the FCC mandated TV Repack a couple of years ago the availability of finding clear UHF spectrum to operate low-power Broadcast Auxiliary Service wireless devices has become very problematic for all users.
You'll find most wireless systems at:
470.0 thru 608.0 MHz along with 941.525 thru 959.850 MHz.
VHF wireless equipment is also widely used on "locally unoccupied" VHF TV Channels 7-13 @ 174.0 thru 216.0 MHz.
Also be aware that low-power wireless equipment is no longer limited to analog only mode... The newest gear is digital and yes indeed, The Big E even exists for wireless microphones.
KP