Thanks for the video. I always wondered what a spark-gap transmission would like like on spectrum analyzer and how wide the transmission would be. That was eye opening.

@joesmith-je3tq

7 ай бұрын

Same here. I figured it was easy enough to setup using a fly swatter for the HV source. While the single stage was pretty poor, I was surprised how well the two stage performed.

ive started making my own transmitter based off this design. the radio experimenters handbook is a very good source for information!

@joesmith-je3tq

Ай бұрын

If you decide to post about it, provide a link so we can have a look. If you would like to see the last transmitter I constructed in operation, check out the following: kzread.info/dash/bejne/e6yAurOddsy_pKw.html

I hope we don't have to wait till next summer for you to show us how that works on flies. And btw, were you going to hold that fly swatter in your hand?

@joesmith-je3tq

7 ай бұрын

Wait for Part II

This is great, but I’m not sure what you did to get the spectrum. Did you connect the input of the analyzer to an antenna? I assume you were tuning with the variable capacitor- why is it so big? Anything special about it ? Thanks !

@joesmith-je3tq

6 ай бұрын

I used few inches of wire for the SA. Yes, it was tuned with the output capacitor. The tuning capacitor is what I had on hand that will handle the voltage without breaking down.

@joesmith-je3tq

6 ай бұрын

There is a Part 2 (see description) where I tuned it back to the 80M band and listened to it with a radio.

@yjweaver5108

6 ай бұрын

@@joesmith-je3tq yes I saw it now - you answered my questions

Did you build this so the flies and call SoS ?

@joesmith-je3tq

7 ай бұрын

Yes!

@NiHaoMike64

7 ай бұрын

I suppose if you had an emergency out in the middle of nowhere, your phone couldn't get a signal or otherwise doesn't work, but you do have an electric fly swatter or arc lighter, some wire, and pieces of metal for making a capacitor with (e.g. food cans), you could theoretically cobble together a transmitter to call for help. (A friend of mine died while hiking in Zion National Park last year, she did have a buddy with her but the lack of communications meant that help could not arrive in time.)

@joesmith-je3tq

7 ай бұрын

@@NiHaoMike64 Sorry to hear that Mike. I'm guessing that the range on this thing, even if I could string up a 160M band dipole, isn't going to be very far. The fly swatter makes for a weak source.

@wktodd

7 ай бұрын

@@NiHaoMike64 Sorry about your friend. I have wondered what could be made with a car ignition coil etc. but cars these days are either diesel or use cap-top coils with bugger all windings . Fancy a challenge Joe?

@wktodd

7 ай бұрын

And / can bloggy spil chocolate

Too wide transmitting spectrum

@joesmith-je3tq

7 ай бұрын

Maybe there is a reason they have not been used in the last several decades....

@rocketman221projects

7 ай бұрын

@@joesmith-je3tq They have been illegal world wide since 1934. They went obsolete as soon as vacuum tubes could output a useful amount of RF power.

@joesmith-je3tq

7 ай бұрын

@@rocketman221projects Spark gaps have been illegal, or in the case of the USA, did the FCC just add a requirement for phase noise? In other words, can a spark be used as a source providing that the output is cleaned up enough to meet what ever phase noise requirements are out there?

@H-77

7 ай бұрын

​@@joesmith-je3tq There's also that obvious challenge of trying to design a spark gap that actually lasts for an appreciable amount of time and doesn't change its characteristics too dramatically as it ages...

@joesmith-je3tq

7 ай бұрын

@@H-77 Maybe use some modern automotive tricks? The plugs in my car are 13 years old.