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RF chokes & bypass caps.

Scott,

You wrote, "Air core chokes are worthless in these (Tesla coil) 
circuits due to core saturation and provide no protection to speak 
of".

If you've had an air core choke magnetically saturate at your 
location, you had better stop breathing that air right now and 
quickly consider a change of address!

I thought you and the group might like to know that I have had 
excellent results with multi-section, universal wound air core chokes 
and I do not employ bypass capacitors with them, just a safety gap
across the output of the 15 KV neon transformer.  Since air lacks the 
permittivity of iron or ferrous derrivative cores, many more turns are 
required.  I've had good success with 240mH chokes and 320mH.
Yes that's three hundred and twenty millihenries!  Thats just a tad 
over ten ohms to the 60 Hz but over 40Kohms to 200KHz RF.  I do
have to immerse these commercial chokes in transformer mineral oil however
to stop the impressive lightning show that otherwise occurs between the 
sections.  I'm experimenting now with winding my own air core chokes
to solve an acquisition problem and have just made a pair of 142mH
chokes (4-sections, 0.5 inches thick, 0.5 inch air spacing,  scramble wound
between 3.75 inch diameter plexyglass (acrylic) washers on a hollow 
1 inch phenolic tube using #22 AWG aluminum enamel covered magnet wire.
(I got a great price on a 20 mile roll!).  I haven't had a chance to 
test these yet but I'll post the results when I do.

It has been my experience that bypass capacitors like 500pF 20KV 
mica doorknobs can quickly overheat a small portion of the secondary 
of a 23mA, 10KV furnace transformer due to a series resonant/localized 
overvoltage condition at 60Hz within the potted secondary and short out
the transformer.

Happy coiling, R.W.S.