Re: Novel primary designs

["Andreas Marshall" <marand-at-t-online.de> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Tesla list wrote:

> Original poster: "acmnovak" <acmnovak-at-email.msn-dot-com>
>
> Hello Everyone,
>
> A while back I was kinda busy and put coiling aside for the time being, but
> now I'm getting the itch... I need to rebuild my whole system which, as I'm
> sure you all know, can be quite costly. Well... If you want a good looking,
> long lasting coil. I decided to start out with the primary and base
> structure because everything else gets bolted to it...
> I was hoping to employ a different type of primary, but so far, all I've
> seen are flat coils made of copper tubing and lexan. Mostly, because these
> materials are the easiest to find and put togather. Does anyone know of a
> place to get info on primaries made of flat copper flashing? I've heard
> those are really efficient and easy to make.
>
>  I would like to try out an Idea from the makers of Electrum, a primary
> that fits INSIDE the secondary. However, wouldn't that give too high of
> coupling for a conventional coil? Great Idea to save space...
>
> How about a spiral coil wound on supports that are shaped like a parabola?
> Wouldn't that give the best distribution of magnetic flux along the length
> of the coil? As long as the focal length is the same as the height of the
> secondary. If TC frequencies propagate anything like standard RF...
> .
>
> Has anyone experimented with litz wire primaries? That would give higher
> inductance with lower turns at high frequencies given the skin depth of TC
> tank circuits...
> The only problem is, you wouldn't be able to select the best tap because
> you would have to make contact with all strands of the wire, thus shorting
> out the other part of the primary which takes away inductance and creates
> eddy currents. You'd have to know how many turns you need before you even
> build the coil...
> Litz wire may be succesfully employed in the tank circuit wiring, as it
> allows a wire to carry more current for it's diameter.
>

Litz wire is not the best material because of its capacitance between the
conductors. In some old Book i read that about ca. 1 to 10MHz
flat conductor plates can be better.

>
> The most practical of the new designs I was thinking of is not all that
> new. Simply adding another layer to a flat coil which allows the two to
> share inductance or whatever, thus requiring less turns. I've never tried
> this, myself, but it is probably the next logical step.
>
> I personally think that two layer copper tubing coils look the coolest : )
>
> Could anyone fill me in as to where I could purchase Lexan?
> I've seen this stuff in many coils and I'd like to get my hands on a big ol
> slab of it.
> Anyway, feel free to make fun of the above Ideas or add to them in any way...
> later
>
>
>                 -Michael