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Unused primary turns, Was Re: Re:Big Primaries, Small Caps


My experience has been, (on more than one occasion), that too many unused
turns detract form coil performance. I don't know why, (I just know enough
to be dangerous), but that's what I've found. I've removed unused turns, and
then soldered them back in later if I needed more turns again. You can do
the test yourself. Just be careful when removing the unused turns so that
you may put them back in if need be. To make a clean cut I used a small
cut-off wheel powered by a air die grinder. A Dremel would work well too.



Subject: Re: Re: Big Primaries, Small Caps

> Original poster: "Al Hassick" <uncadoc-at-juno-dot-com>
> You know, I am curious about something, since you are on this subject
> about big primaries.  I have my 3/8" copper refrig. tube primary tuned at
> the 7th loop from the center, and it has a total of 14 turns in all.  It
> seems the more doorknob caps I add to the tank circuit, that the less
> primary coil I need to tune my 8" secondary for maximum spark.  But what
> I am trying to get at is this,  do I really need the unused outer turns
> of the primary as I increase the efficiency of my coil.  Do the unused
> outer turns contribute anything to the circuit?  A small thick primary
> would take less space.  But before I cut it off, say at about nine turns
> I would like to know if anyone has removed unused turns from their
> primaries with any ill effects?  I do remember when I first started
> coiling and used bottle caps, that I needed  as much primary coil as I
> could get.  I even added on a length of tube just to get the coil to fire
> and ran the coil  tapped at the very last outermost turn.  But as I added
> bottle caps, it seemed I needed less primary winding, and the doorknob
> caps needed even less primary tubing.  So, do we really need all that
> unused tube once we get our coils tuned and running? I am looking for a
> smaller, lighter package with max spark in a yet to be built future coil.
>  Al.