The simulcasting technique: An approach to total-area radio coverage

The simulcasting technique described provides total-area radio coverage on an automatic basis where the use of multiple transmitter and receiver sites is required to achieve acceptable communications coverage over rugged terrain or wide areas. In this technique the same audio information is simultaneously broadcast over several transmitters operating on a single nominal-carrier frequency. Special attention must be given to transmitter-frequency stability and audio envelope characteristics. A master tone-distribution system is essential when incorporating a continuous tone-controlled squelch system (CTCSS). Use of the simulcasting technique reduces effects of fading in a mobile environment through transmitter space diversity. An application of the simulcasting technique to a coordinated FM-UHF law-enforcement communications system in Orange County, CA, is described.