Re: Is high coil frequency a bad thing?


My first coil operates around 450kHz (I dont remember exactly). It is a 
small 3" dimater by 15" tall coil that by itself resonates at real high 
freq, but I have tamed that way down with a big 21"x8" stovepipe toroid. 
So far this is as big of toroid I can put on it until I tap in a few 
more primary turns. Putting this big toroid on it brought spark length 
from around 20" to 29" using 12kV 60mA. I dont know how much of this 
increase is due to lowering the frequency, but I amagine most of it is 
due to more primary turns and more secondary capacitance. This is a 
super efficient coil, but for its size it isnt too bad. I am very 
pleased with it - atleast until I started getting secondary flashover. I 
am not an expert but I would say not to care so much about the 
frequency, just try to get as big of toroid on it as you can - 
experiment with varius sizes if you have the resources to.

Tristan Stewart, KC2EBM

>Original Poster: Doug Brunner <dabrunner-at-earthlink-dot-net> 
>I'm redoing the math for my coil, and it looks like one of the best
>options (in terms of wire availability and spark breakout) would 
>running at a fairly high frequency (440 kHz or so). Would that tend to
>diminish performance relative to operating around 100 kHz?
>           --Mr. Postman (Doug Brunner)
>                <dabrunner-at-earthlink-dot-net>

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