Radio Microphones

Radio microphones (or wireless microphones) are microphones that are not directly tethered to any sound recording equipment, for instance a sound recorder or video camera.

Commonly referred to as radio mics or wireless mics, the original cable used has been substituted for many different frequency transmission technologies. Radio mics can now transmit audio through radio waves in FM, AM, UHF, VHF and various digital formats.

More advanced models will allow you to select various frequencies to transmit over, helping avoid interference with other electrical transmitters that might be using the same frequency, and also enabling the use of multiple radio microphones at the same time.

It is thought that the very first radio microphones derived from the first compander microphone invented in 1976 by Nady Systems, who was honoured in 1996 with an Emmy award for his technical contribution to the field. 

Advantages of Radio Microphones
Using radio mics creates a series of advantages for the user. Firstly, on a practical basis you eliminate any trailing cables which can and do cause potential trip hazards. Secondly, as a result of this, you allow the wearer of the microphone the freedom to walk around untethered. Another advantage is that you eliminate the stress placed on audio cables that flex and often break due to movement.

Disadvantages of Radio Microphones
For all their merits, radio microphones do indeed have a few disadvantages. Firstly, two way radio batteries can be very thirsty and do not always last very long. Radio mics are also limited by range, with the more expensive/powerful models being able to transmit the signal furthest. There is also the possibility of interference from other electrical items which could disrupt the signal. Lastly, you are limited to the number of radio microphones you can use at the same time due to frequency clashing.