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Re: Final Confirmation before Building



Original poster: "Jason by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jasonp-at-btinternet-dot-com>

Hi Patrick

> Since I have several NSTs, I want to "overbuild" my coil, such that it can
> handle more power in the future. Initially, I'll just be using
one...so....
This sometimes doesnt work. What I do is overbuild things like my cap and
gap, then make the coil so it is more matched with the power supply. That
way I can save money on gap + cap by not having to replace it, but replace
the secondary and primary.

> Input: 15kv/30ma NST
> Secondary: 6" PVC, 30" wrapping, #24 guage. A bit more than the standard
> ratio, but I've read these dimensions aren't exact, and a higher coil will
> reduce primary sparking.
The 6 by 30 works fine - its what I use. The coupling is a bit sensitive,
but it works really well. Power is also fine - no probs there. 450VA should
run it fine - just dont make the topload too big or you won't get any
breakout :)

> Primary: Approx. 65' of 1/4" copper tubing, for a total of 15 turns with a
> spacing of 1/3" and an inside diameter of 8"
> I'm not sure on that 1/3" thing.....that's what QuickTC told me. (0.308"
to
> be exact)
That sould be OK - i use a spacing of about 8mm (0.25" ?) and I dont get
arcing, thats on 10KV. ith 15KV that should still be fine.

> Spark Gap: Not sure at all. QuickTC says 4 gaps, with .308 spacing for
> "safety +10%" and .07 for "individual". So I'm a bit confused as to what
to
> do with this. I think a RQ gap would be best, but I still don't know the #
> of gaps or the spacing.
With 15KV is is not too hard to make an RQ gap - I would personally go for
10 pipe sections that are 1mm apart. you can generally take the breakdown
voltage of air to be 1mm/division, which gives you a 10KV gap. Now add a
good sucker (like a vaccum cleaner or a centrifugal pump) and you should be
good for 15KV. Or alternatively make each gap 2mm wide and then tap the
tubes for different gap voltages.

> Caps: Salt water caps (for now) arranged such that I can choose to use
> either 6, 8 or 12.
SW's are actually not that bad - I reckon that you loose about 10% power but
they beat all other caps for cheapness!!! After you have got tired of them,
then go for an MMC - I believe the geek group's caps are pretty good.

> Safety Gap: Just a simple adujustable gap using 2 screws, with a grounded
> terminal in between......what do I ground this to? RF ground or mains
> ground?
I would stick the safety gap to RF ground, that way you dont get loads of
crap going back into your house line. I would adjust the safety gap so it is
slightly too wide for the neon to fire the gap (on its own) and then adjust
it to get the best streamer length. To be honest it really isnt neccesary to
use a safety gap, especially on a static gap system. With an RSG or a
resonant cap you should always use one, but not really for a non resonant
static. Always a good habit to get into though...

> NST Protection: None at the moment - a bit to complicated for me.
Not too much of a problem. Some people claim that their trannies work fine
without protection, others swear that is is needed. Personaly I err toards
the cautious side - Neons are hard to come by in Britain, so I prefer to
spend that extra 20 quid and play it safe :) your choice though!!!

As an afterthought, I would consider building an MMC cap as soon as you get
some cash. You will probably get over 20% streamer increase length with an
MMC over a SW cap, but SWs are fine for the time being. Another tip - keep
the RF ground cable as short as poss, and the RF ground piupe as deep as
possible.

Anyway enough from me :)

Good luck,

Jason