Pages: (1) (2) (3) (4) (5) (6) (7) (8) Modulation page // Oscillator Page

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The amplifier that the microphone talks into is probably the same audio amplifier you use in your receiver. I'll bet that if you've got a transceiver, which is a transmitter and a receiver in one handy squawk box, that it uses a lot of circuits for both sections. After all, transmitting is just receiving in reverse. Walk over here with me to this bunch of glowing electrical machinery.

This here is the modulator, and it's another audio amplifier. "Modulation" is detection in reverse: we mix our voice signal with the radio frequency signal which will carry it out into the air. It doesn't matter how much we amplify an audio signal, it just won't radiate off your antenna, it's too low a frequency. That's why we need a carrier, and we'll see how it is produced in a minute.

I'll have to ask you kids over there not to spill your soft drinks on the circuit board -- you'll make everything sticky and the guy who owns this rig we're talking through won't know what's happening next time he opens it up! (Next page -->)

From The Big Dummy's Guide to C.B. Radio, courtesy of The Book Publishing Company P.O. Box 99,Summertown, TN 38483 (888) 260-8458, (1976). Editors: White Lightning (Albert Houston) WB4BWR, Stringbean WA4LXC (Mark Long), Minnesota Mumbler WB4KDH (Jeffrey Keating), Ratchet Jaw K4IAP (William Hershfield), Buffalo Bill WA4KCF (William Bradley) Illustrations by Mark Schlichting and Peter Hoyt.