Re: First Coil Works --Tuning Help

To: tesla-at-pupman-dot-com
Subject: Re: First Coil Works --Tuning Help
From: Esondrmn-at-aol-dot-com (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Tue, 17 Nov 1998 12:10:53 -0700
Approved: terryf-at-verinet-dot-com

In a message dated 11/16/98 5:39:31 PM Pacific Standard Time, tesla-at-pupman-dot-com
writes:
                -   snip    -
<< Adam,
 
 Sounds like you are making good progress.  You haven't provided enough
 information for me to do any calculations for you.  I use a spreadsheet that
I
 put together (it is available at Chip's web site and at the ftp site) to do
my
 calculations.  It is set up to first calculate the paramaters for the
 secondary, then you input the primary information and it will calculate the
 required tank capacitor.  I do all this first then play some what if with the
 numbers, by for instance changing the number of turns input for the primary
 until the calculated capacitance matches the amount of capacitance that I am
 using.  This might be 10.5 turns - which is where the coil should tune, plus
 or minus a turn or so.  It gets you in the right range anyway.  Another
method
 is to calculate how much primary inductance is needed in conjunction with
your
 capacitor to match the resonant frequency of the secondary - then use the
 spreadsheet to vary input numbers to the primary calculations until you
 achieve the required inductance.
 
 Ed Sonderman
  >>
Replying to my own post:  For those of you using my spreadsheet, please take
note that the formula for calculating the required capacitor uses 90% of the
primary inductance.  This is so someone doesn't build a coil that tunes right
at the end of the last turn on the primary - i.e. it builds in some tuning
room.  For playing what if calculations you need to modify that formula so it
uses 100% of the primary inductance.  Change the formula located at I 89 (that
is cell i 89) from =.9*D66  to  =D66.

Ed Sonderman