Simple RF Transmitter

Posted on Feb 4, 2014

This schematic is a tone transmitter. For sufficiently small values of the resistor, it outputs a tone, so having a resistive mic (carbon mic) in parallel with or in place of the resistor. would modulate the tone frequency with the voice. I`m not sure how you`d be able to demodulate it though, so this may not be the best circuit to use as a voice transmitter. Sorry about my last post (and for bumping), it would NOT go in place of the

Simple RF Transmitter
Click here to download the full size of the above Circuit.

capacator but as said before, it would be used like a resistor to control the capacitor. Hi All that is a very interesting cct. I built one almost exactly the same and it was shown as an FM transmitter. I. e. frequency modulated. Sure enough I could pick the carrier up on my FM radio about mid way on the scale. I was wondering how to put the audio/voice signal in when I noticed tapping and knocking noises coming up on the radio and a moved my physical circuit around !. The wound coil was vibrating and altering the frequency which was of cource then being picked up on the FM receiver as frequency modulated signal ! So for a microphone you could try glueing the circuit to a bit of brick and attaching the coil to a window. That way the window would pick up voice signals and mechanically feed them like a big microphone through the circuit into the FM radio receiver. I havent tried this yet but if I see any replies to this post I will get my circuit out again as I still have it and a few other similar ones I was playing with for my data transmission project.

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