Simplex Operations

Simplex operation is a direct radio-to-radio method of using a radio, in which all users receive and transmit on the same channel; it is the most common type of operation that people are familiar with. You turn on the radio, dial in a channel (or frequency), and start talking. So long as everyone is on the same channel with the same squelch settings, and everyone is in range, all parties can hear one another.

Simplex operation generally works well over shorter distances, or when communicating using a base, mobile or handheld station that’s in a high location. Since there is no repeater, coverage is generally limited to a few miles, although depending on topography, much greater ranges may be possible. It is most easily deployed in the field among groups of people.

The GMRS service has the following 22 simplex channels defined by the FCC: