A wireless microphone transmits sound without a cable. Also referred to as a radio microphone, it functions through frequencies and transmission technologies, particularly UHF or VHF frequencies, FM, AM and digital modulation schemes.
Benefits of Wireless Microphones
The main advantages of a wireless system over a wired one are convenience and mobility. A wireless microphone allows a user to freely move around without the worry of tripping over cords.

VHF and UHF
In terms of technology and function, UHF and VHF follow the same principle of operation. The primary difference between transmissions in UHF and VHF is their frequency or band. A VHF system operates within 150 megahertz to 216 megahertz, along with VHF TV channels from 7 to 13.

A UHF system operates within bands between 470MHz and 698MHz.

Advantages of UHF Over VHF
Although both UHF and VHF follow the same technology and function, UHF has less risk of interference because it uses higher frequency ranges. This becomes very beneficial to wireless microphones, because of the risks of interference from many other wireless systems that typically use lower frequency ranges and radio signals.