more vttc testing

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Original poster: "claude masetto" <claudmas-at-optusnet-dot-com.au> 

Hello,
I have just finished more testing on the vttc tonight and I believe I know
what's going on.
If I run it to full power and to the 30" output the frequency still remains
at 255khz.
If I attach a 30" piece of wire to the topload the frequency measured with a
signal generator drops to 320khz and if I attach a second piece of wire it
drops to 260khz.
The antenna pickup is measuring the primary LC circuit oscillations and as
the power is increased the sparks become longer loading the secondary and
bringing down its resonant frequency closer to the primary until, if your
lucky, it matches and the whole thing works as it should.
Very interesting.
That means it is not easy to tune because you don't really know what the
final frequency of the secondary will be. To tune the primary you can vary
inductance and capacitance whilst observing output length, current draw and
tube redness and seeing how all these change for better or worse.

Claude.