Roger, it’s also good to know there are a finite number of frequencies available. Your frequency is used by others… the FCC (or a certified outside group) coordinates the use of these frequencies. They used to, or still are, spacing them a distance away from each other-it was a 70 mile radius as a rule of thumb before they allowed some other agency the use of the same frequency. Agencies using the same frequency 70 or better miles apart may still be heard, although weak, heard non the less. It is bothersome. That’s where PL’s came into use… a sub-audible tone or mix of tones would be transmitted along with the audio transmission. And only those radios listening to the same PL tones would open up their receiver and hear the audio. FDNY could be heard in central Ct on their VHF frequencies which are also assigned to Ct FD’s. But no one bothered the other because all were assigned differing PL’s.