3. Radio Frequencies
FM wireless systems can be divided into two groups - those which operate in the VHF (Very High Frequency) range and those in the UHF (Ultra High Frequency) range.
|VHF||30 MHz to 300 MHz||traditionally used in the transmission of radio programmes|
|UHF||300 MHz to 3 GHz||traditionally used in the transmission of television programmes|
Although typically a little more expensive, the UHF range dominates the market for guitar wireless systems as it tends to be more reliable, especially when using a multiple transmitter / receiver setup. This is because the higher the carrier frequency, the broader the available bandwidth. This translates either to the availability of more individual channels, or to greater frequency separation between channels. Either way, the potential for the collision of radio signals is reduced, and reliability is increased.
Carrier frequency is a slightly misleading term, as transmitters / receivers normally operate at frequencies near the carrier frequency. Carrier frequency can be thought of as the average or centre frequency of a radio system - the different channels are formed using deviations from this frequency. Some channels are set to a unique value above the carrier frequency, and others to a unique value below, in order to achieve the required isolation. This is why we talk about the bandwidth or frequency range necessary for multi-channel links.