FM noise squelch

Although the squelch (noise suppression) function on most narrow-FM transceivers (including CB rigs) will work fine without too much attention being paid to it, there is always room for improvement. In this article we look at a better squelch which is intelligent enough to suppress almost anything you do not want to hear, including those nasty 'empty' carriers, constant whistles and a lot of other interference which always seems to be around, particularly when going mobile. At the same time, the FM noise squelch maintains a variable switching threshold to make sure that you can hear the other station even if its signal swings back and forth between 59+ and just about the minimum detection level of your radio. Suitable for any CS or radio amateur transceiver with a selective tone-call extension socket.