CW Coil FFT Measurement

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi All,

I took my CW coil and ran it at about 500 watts input (500 forward ~~200
reflected, not tuned all that great ;-)) so it had about a 300 watt
flamming arc.

http://hot-streamer-dot-com/TeslaCoils/MyCoils/CWCoil/300watts.jpg
http://hot-streamer-dot-com/TeslaCoils/MyCoils/CWCoil/P1280005.jpg
http://hot-streamer-dot-com/TeslaCoils/MyCoils/CWCoil/P1280006.jpg
http://hot-streamer-dot-com/TeslaCoils/MyCoils/CWCoil/CWDig.jpg

I set up my fancy Tek 3012 scope with my plane wave antenna and got the FFT
thingy going.  With the antenna about three feet away, the output looked
like a very pure fundamental.  NO harmonics at all!

http://hot-streamer-dot-com/temp/CWFFT01.gif

20dB/div vertical, 250KHz/div horizontal.

http://hot-streamer-dot-com/temp/CWFFT02.gif

The generator supplies a very pure sine wave to the coil (>55dB) but the
arc does not seem to generate significant harmonics.  I am unsure of a
fancy over computerized digital scope being nearly equivalent to a "real"
spectrum analyzer, but it should have easily picked up any "noise" if it
was there.

Maybe tube coilers and such don't have to worry quite as much about the
FCC's black vans (they are really white "federal government" (cheap) cars
with $150,000 worth of "stuff" in the passenger's seat) ;-))  The playroom
is filled with battlebot stuff at the moment, but I hope to try it on a
disruptive "real" streamer coil soon.

Cheers,

	Terry