Simplex Operation

Simplex is a means to communicate between radios without a repeater

We periodically test our ability to reach far away stations via simplex. This is important in an emergency in case no repeaters are available. Traffic can be relayed from station to station to eventually arrive at the intended recipient.

San Mateo County conducts simplex drills and so does SC4ARC. After the test, a matrix can be drawn up showing who can communicate with whom.

We use the Circuit Merit system to rate the quality of the reception. CM5 is the best with no background noise. CM0 means nothing was heard.