Jaycar AM Morse Code Transmitter
Continuing from yesterdays blog:
https://wb9kzy.blogspot.com/2025/12/short-circuits.html
Here is a simple, fun, discrete component AM Morse Code Transmitter from the Short Circuits volume 1, page 30:
The circuit shows .1 uF audio timing caps for the flip flop but I changed them to .22 uF which lowered the frequency to about 660 Hz:
I can't remember where I got the ferrite antenna but it was the only one I had with 4 leads:
After hooking up the last transistor I got these waveforms at about 480 kHz:
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| damped carrier |
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| about 6 div x .25 ms per div = 1.5 ms period or about 670 Hz |
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| damped carrier, 4.2 divisions x 500 us per division = 2.1 us period or about 476 kHz |
The bell shaped decay - is this similar to how a spark waveform would have looked ? Anyway a functional simple circuit, worth trying but it needs work. It is lower in frequency due to the scope probe capacitance as well as the solderless breadboard capacitance.
The Short Circuits volume 1 circuits are constructed using spring clips plugged into a plastic base with a grid of holes that remind me of the old Radio Shack Science Fair red P-boxes:
As I recall those spring clips from Radio Shack must have been plated with silver ? Because all the ones I have got tarnished.
Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm
