Botherance rejection with double-barreled channel guard

A number of solutions to the Land-Mobile Communications "botherance" problem are discussed. Tone coding is shown to be a practical and expedient method of rejecting botherance by the use of a continuous, tone-controlled squelch system. The requirements of such a system are given, and a design satisfying the requirements is explained. A novel method of modulating the transmitter is shown and a method of including both noise-operated and tone-operated squelch systems in the receiver in order to provide automatic channel monitoring before transmissions is discussed.