Re: primary base construction questions

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "J. B. Weazle McCreath" <weazle-at-hurontel.on.ca> 


At 05:37 PM 01/11/03 -0700, you wrote:

 >Original poster: Adam Britt <beans45601-at-sbcglobal-dot-net>
 >
 >I am in the process of building a final primary base for my 8" PT coil
 >What have all of you discovered is a good material to build it out of?
 >
<SNIP>
 >Does it effect the performance if you have the primary right next
 >to the ground?
 >
<SNIP>
 >How do you make your base to where the secondary will move up and down,
 >easily?  I need some way to adjust coupling.
 >
<SNIP>
 >Thanks, Adam, KD5WIT
 >

Hello Adam, Coilers,

For my primary supports I've just gone to WalMart and bought several of
their white plastic cutting boards as used in the kitchen.  It cuts and
drills like a charm, is a great insulator, and best of all, they're not
very expensive.

You definately don't want your primary close to the ground, as you will
have a lot of loss.  Several feet off the floor is fine.  I built up a
table of sorts with a lower self about eight inches off the floor where
the MMC and gap are located.  About 15 inches above that is the top of
the table which supports the primary and secondary.

A lot of the guys move their secondaries up and down to vary the degree
of coupling, but I find it mechanically simpler to raise and lower the
primary.  When I wind my secondaries I always start my first turn a few
inches or so up from the bottom of the form.  With the primary supports
resting on the top of my table, the coupling is very loose, but simply
by putting spacers under the supports I can adjust the coupling easily.

Once the optimum setting for the coupling has been found, it's a simple
matter to secure the primary supports in a more permanent and better
looking fashion.  I just feel a lot safer having my time and labour
intensive secondaries and toroids mounted securely.


73, Weazle, VE3EAR/VE3WZL

Details of my "Hyperbaric Gap" and Tesla coil are at:
http://www.hurontel.on.ca/~weazle