RE: Edge Wound Primaries

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

Edge-wound helical coils are sometimes used in RF tank applications
because they have higher Q's and lower losses due to lower proximity
effect, as the spacing between turns is maximized, while minimizing
conductor and winding length.

It's not uncommon to build flat pancake primaries wound with ribbon
stock, as this is far easier to construct, and may (?) benefit from the
lower proximity effects, but I'd worry about eddy current losses.  I
doubt there's an easy way to build an edge-wound helix without some very
specialized equipment.  And how much these benefits and losses will
actually affect spark performance remains an open question.

Regards, Gary Lau
MA, USA


> Original poster: "Angelini, Frank J" <FrankJAngelini@xxxxxxxxx>
>
>   I have several old magazine articles from the 1920's - 40's.  Many
> of the TC's advertized for purchase had edge-wound  primaries. They
> used thin copper or brass ribbon stock, approx 1/2 - 3/4 - inch
> wide.  Why was this design used?  Is there an electrical
> advantage?  I have also seen this method of coil winding used in ham
> radio gear.  Is special machinery required to edge-wind a primary
> coil or can this be done in a home workshop?
>
> Thanks