Electronic Fly Swatter, Spark Gap Transmitter Sound Part2

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@DM-fz3ly 10 ай бұрын

Not only entertaining and useful Joe but FASCINATING also!! would love to actually see both the spark input sawtooth and also the 4 MHz ringing on an O-scope. This is really neat stuff!! thanks for taking the time! Been a ham for many years and yet there are some concepts that just did not come to light or catch my interest. Always thought spark gap was a horribly wide noise burst but here you show that it is actually relatively narrow and not so horrible after all.

@joesmith-je3tq 10 ай бұрын

Sure, I can do that for you. See the attached link: www.eevblog.com/forum/rf-microwave/fly-swatter-ham-radio-transmitter/new/#new

@shazam6274 11 ай бұрын

From the "Big Bang" to the "Nano Bang".... White Noise at its finest! When I was a kid, and listening to shortwave radio, there were quite a few transmitters operating like this. I think they called them "keyed noise" transmitters.

@gamiwv 11 ай бұрын

Very nice key. I have that one (legacy) from my father (He was professional radio officer) 73 de SV1ZH

@joesmith-je3tq 10 ай бұрын

Very cool. I'm not skilled enough to do the key justice. I had the weight all the way to the rear and even then it's too fast. Check out someone that knows what they are doing: kzbin.info/www/bejne/aJKXpJajoahqqqs

@ktheis1 11 ай бұрын

Next: rotary spark gap. Love to hear one!

@rocketman221projects 11 ай бұрын

Then a Poulsen arc converter after that.

@joesmith-je3tq 11 ай бұрын

With it running from the fly swatter and DC, it's basically cycling as fast as it can charge the cap. I didn't measure it. I'm not sure how this would compare with the cycle time of a rotary gap. I could ditch the fly swatter so we could control the frequency.

@joesmith-je3tq 11 ай бұрын

@@rocketman221projectsI did some reading on the Poulsen oscillator and never saw them running over a few hundred kHz. May be fun to see if it is possible to make one run faster.

@ktheis1 11 ай бұрын

@@joesmith-je3tq to be honest, I was thinking of a mechanical device. But....if I were to do it electronically, I might go with a square wave osc driving a transformer with a huge turns ratio on the secondary. Maybe a 555 type or an old motorola Motrac hv supply with a different transformer. Hmmm. I was surprised just how much attenuation you got by tuning your circuit. I always thought the spark signal would be mhz wide even with a tuned network on the output, but you getting a couple hundred khz before the signal went down into the noise really surprised me. Thanks for taking the time to do this!

@rocketman221projects 11 ай бұрын

@@joesmith-je3tq There was probably no need to run them at higher frequencies back then. They were mostly used for high powered, transoceanic stations. At the time it was believed that only VLF and LF would work for long distance transmissions. In the 1920's when it was discovered that HF could be used for long distance communication, spark was already on its way out.