An interesting plasma speaker using a Tesla coil

fgentges at fgentges at
Mon Mar 26 13:00:43 CDT 2007


A number of years ago I had a Johnson Viking Desk Kilowatt on the air. 
I made up a 3.7 MHz Tesla coil.  It was just a 3 inch piece of plastic 
pipe with a couple dozen turns and very sensitive to the number of turns 
etc. for the resonant frequency.

The rig loaded it up and a nice 3 inch corona was formed off of the top 
screw.  With modulation, the corona made a very nice speaker that was 
very crisp but lacking in bass.

Loading a KW into a 3 inch corona is not an efficient loudspeaker but it 
makes a nice physics demonstration.

Frank K0BRA

Bob Bruhns wrote:
> I did something similar at a radio station back in 1967. I jammed a wad of steel woll into the arc gap at the base of the main
> tower. The steel wool caught fire, and I could hear the station audio in the arc. But one of the engineers drove up, because the
> station had suddenly started splattering the whole broadcast band! I was SUPPOSED to be digging up ground radials for
> maintenance, so I got back to that.
>   Bob, WA3WDR
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