[Boatanchors] Making coils

[J. Forster]

Sandy and Kees Talen wrote:

. What are the advantages ?

Your answers are correct below.

> Since the Litz wire is multistrand, the surface area is increased which should
> improve it's capabilities at higher frequencies due to "skin effect", the coil
> "Q" may be higher because of this, and since it's not "round" it would lay in
> place better.

> Is the main reason for the pattern winding to keep the turns in place ?

Depends on your coil, but in general no. Winding a simple multi-layer solenoid
will drastically increase the interwinding capacitance and lower the
self-resonant frequency.

> In other words, if you were winding on a spool, you would be OK by just
> winding uniformly ?

Only for very low frequency coils.

> The drawback would be finding the small stuff at a reasonable price.

What size do you need? How much of it? Please reply off-list.

> Magnet wire is cheap, might require the use of bobbins to get it to stay in
> place (although JW miller solved this with enough adhesive), and maybe
> multiple strands of #38 has the same effect as Litz wire.

Depends on operating frequency (skin depth) . Small signal Litz typically uses
#44 or smaller and 50 + strands. Any copper under the skin depth is esentially
wasted. Litz made up of multiple strands of #38 would be more usefull for ferrte
power transformers or baluns.

> Would it have to be twisted ?

Yes, for mechanical reasons at least.

> Is the only reason for the winding pattern to keep turns in place ?

No. See above.

-John