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Re: Weird Magnifier output

Hi Dwight,

	Check a few things...

1.	Be sure the scope is well grounded on a different ground and circuit
than the coil.  In other words be sure it isn't picking up noise through
the AC or ground wiring.

2.	Be sure the input signal is within the measurement range.  If the input
amplifiers on the scope are clipping the signal, all kinds of funny things
will be seen which are not really there.

3.	How are you picking up the signals?  You "should" be using some kind of
50 ohm radio (CB, scanner, cell phone, etc.) antenna.  That antenna needs a
50-ohm terminating resistor at the input to the scope (that scope may have
this function built in if it hasn't been fried.  Check through that scope's
zillions of menus and check it with an ohmmeter).  If you just hang a wire
on the end of a scope probe, the probe circuit will ring and cause strange
things to be seen.  The antenna setup mentioned will be properly terminated
and balanced and will not have unwanted harmonics bouncing around in the
cables and such from the coil's impulses.

4.	Short the scope's input and be sure the signals disappear.  If they are
still there with the input shorted, well.... :-)

5.	The scope's sampling rate and the intermittent pulse nature of the coil
may be confusing the scope's FFT function.  If that is the case, there is
probably some work around but problems like that make my brain hurt :-))

6.	If the arcs are striking ground, you may be seeing some harmonics from
the current discharges.  Also, the spark gap may be putting out powerful RF
noise too.  Just have to play around with it to see if these are the cause.

That's my list of things digital scopes and Tesla coils do to mislead their
masters! :-)

Good luck!  Sounds like your are doing some really neat testing there!!

	Terry
	terryf-at-verinet-dot-com


At 08:21 AM 12/15/98 -0500, you wrote:
>
>
>Hello All,
>
>    I finally got my magnifier working but I got unexpected spectral
>outputs.  The scope that I have on lone is a Tektronix TDS 460 that does
>Ft's.  Using a 0.08uf cap and appx.30 uH of tapped inductance on the
>primary of the RF transformer( the 30 is just a guess, I calculated it and
>measured it but I have sense forgotten it while writing this post) I got
>strong hot discharges from the resonator to the ceiling which is the
>closest ground.  I can not see the full output due to this problem of close
>quarters in the basement.  With the 5KVA pig, moving it around now is
>impossible to do by myself.  Anyway, the FFT showed three peeks; one at 140
>KHz and 370 KHz and a braud one ate 560 KHz. The latter being the RF
>transformer.  About a month ago I posted the specs of the system.  Well in
>a magi system you want to tune the RF transformer to the resonance of the
>resonator which in this case is 200 KHz.  When I tried  and succeeded in
>getting peek at 200 KHz I got no out put and the safety gaps fired
frequently.
>    Obviously the system wants to run at the 140 KHz mode.  By connecting
>up the RF transformers secondary to the bottom of the resonator is dropped
>the resonant frequency of the resonator.  Is this right?  Any input is
>appreciated.
>    I am getting good quenching with a 12" dia. rotory and a 8 stage series
>blown quench gap.  After 1 and 1/2 periods it quenches.  A clear envelope
>is seen.
>
>    Thanks for any comments that may help in clearing this confusion up for
>me.
>
>Dwight
>
>