A frequency is a path or "channel" used for communications. It is a spot on a radio band identified by its number. In a conventional radio system, one frequency is used for each channel of communication. For example, my local police department’s main dispatch frequency is 154.7250 MHz and the car-to-car frequency is 155.6250 MHz. In a trunked radio system, many channels (or users), share a set number of frequencies. See our Trunked Scanning Page for more details.