Re: Helical top loads

[FutureT-at-xxxxxxx (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

In a message dated 11/23/00 10:28:17 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:

> How can I tune my coil for max. length?
>  
>  Is my 3.5" X 20.5" toroid too big for my 12/30? Should i get more power?
>  
>  What is the max. streamer length i can get off of a 12/30 on a 6" coil?
>  
>  Thanks in advance,
>  Michael Deegan
>  

Michael,

The tap point position along the primary has to be adjusted
(moved) to find the best spark output.  IN other words, use
a suitable number of primary turns for best spark output.
Some turns may be unused.  An important point is that if
you don't have enough capacitance, then you may need more
turns than you have in the primary.  The easiest solution in
that case is to add more capacitance until the coil tunes,
and the spark output increases.  You didn't mention where
your tap point is now.  If you're right at the outer turn, and
if tapping inwards reduces the sparks, then adding enough
more capacitance will give you enough tuning range.

The toroid is not too large, I've used a 5" by 20" dryer duct
toroid with a 12/30 in the past, and gotten 42" output sparks,
(37" sparks with a static gap).  42" sparks are the longest
I've gotten from a 12/30 NST.  My coil that uses a 12/30 NST
is at:

   http://hometown.aol-dot-com/futuret/page3.html

John Freau