[TCML] New 3.5" Coil - A kick in the right direction please!

["Grant Visser" <freeekyg@xxxxxxxxx>]

Hi there,

Suffering from sleep deprivation or 18 hour research / calc / sim /
research .... info overload at the moment, or BOTH! lol

With my limited budget I am on a mission to get a solid base design
into my head before I begin throwing things together as I did last
time! *grin*

The problem is that I have now done so much reading of content from so
many different viewpoints (over the years) that I have confused myself
COMPLETELY! Thus, I humbly beg your assistance ... or at least just a
darn good kick in the right direction!

I have in front of me 26.06" of 3.543" Plexiglass tubing with 3mm
(0.1181") wall thickness (and don't want to waste a single mm of it!)
lol
Assuming 220V 50Hz mains and 2x 9KV/40mA NST's to power my new
coil(/s) (could add another 2 very soon!!!)
3Kg of Double insulated magnet wire about to be ordered, ex works in
either 0.335mm (0.013188"), 0.355mm (0.013976"), 0.375mm (0.014763"),
or 0.4mm (0.015748") OD
Have tried my best but am not going to be able to afford the (less
than ideal) caps for a solid MMC so have decided that I will build a
quality bank of vertical plate caps for this coil. They'll never go to
waste!
I have also decided (I think) to go for a balanced split cap tank design.
Until I can find a decent blower I'll be using my current suction
quenched adjustable 2 gap design.
1/4" copper tubing for the flat pancake primary coil
Oh, and yes I do now have a SOLID and dedicated RF Ground.
I do also have 3phase at my disposal .......

Although it didn't even cross my mind initially, one of my biggest
stumbling blocks at this point is at what frequency I am going to run
this coil. This quandry started when I read a few posts from awhile
back regarding the primary winding and that it should have no less
than 12 to 15 turns and tuned at no less than 9 turns, and ensuring
that the final diameter or the primary is the same or close to the
winding height of the secondary! Apart from the fact that it actually
made sense to me from a coupling point of view, it also meant that I'd
be able to use a smaller main cap, so I was very happy right up until
I started doing the math / sims and it meant that I was going to have
to use a "SMALLER THAN RESONATE" capacitor which, seems to be an
absolute no no if I have understood the numerous other posts and
articles I have been reading!

A further brainmangler that has crept in now is the other concept that
I had forgotten about ..... and that is that I would want to design my
secondary to have the length of wire I need to resonate with my
primary at a 1/4 wave! ie. At 220KHz the 1/4 wave is at 1118.1818ft
and I should thus use exactly that length of wire to coil my
secondary. Again this all makes perfect sense ....... right up until I
start doing the math and the sims ....... at which point, depending on
which program I use to model my coil, either the program yells insults
at me, or I simply cannot find a workable solution which allows me to
use all of the data above AND have a resonate coil with a decent hd
ratio! Going much below 220KHz means that I would have to increase the
length of my coiling wire to seemingly crazy HD ratio's!

Now I do absolutely want to achieve the longest possible sparks from
this coil and I would like it to be an unstressed system allowing long
run times. I would also however like to use this coil to begin
demonstrating and researching the concepts of powering up light bulbs
etc from the ground waves for which I am going to have to construct a
top load with no breakout! With this in mind I was hoping to either
split the 26" form in half allowing me to coil two seperate identical
secondaries and use the second in a magnifier configuration. OR .... I
was even considering (but had not yet begun much research) using the
form for a BIPOLAR coil!

I do realise that 3.5" is not exactly a MEGA COIL but it did seem to
me that it could be a nice little testbed to get me started with some
of the more interesting experiments! ???

SO! Thats where I stand at this point! More confused than ever and
really hoping that you will be able to help me back onto the straight
and SPARKY!

Grant Visser
Randburg, South Africa
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