[Boatanchors] Making coils

[Sandy and Kees Talen]

I'm playing around with some homebrew RF coils, RF 
transformers, etc and will put together a coil winder in the 
near future.

My question is about wire. I have plenty of magnet wire up to 
#38AWG (from good ol' swapmeets), however, the earlier 
aplications used Litz wire but the "modern" (60's) JW Miller 
coils seem to use magnet wire. What are the advantages ?

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. Any other 
reasons ? Is the main reason for the pattern winding to keep 
the turns in place ? In other words, if you were winding on a 
spool, you would be OK by just winding uniformly ? The 
drawback would be finding the small stuff at a reasonable price.

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. Would it have to be twisted ? Is the only
reason for the winding pattern to keep turns in place ? Any
other comments ?


73s  Kees K5BCQ