[Lf] Really big coils

[Andre' Kesteloot]

Cantrell Bill-QA0057 wrote:

> Winding a coil from aluminum CATV line, etc. would be similar to using wide
> flat strap for the conductor.  This is actually less effective than using
> Litz wire at LF with the proper strand diameter to # of strands ratio.  Its
> a fractal-geometry thing involving the skin effect.  You get far more usable
> surface area with Litz wire in this frequency range than you can get with
> flat strap or big dia conductors.  (Think of it this way -- there must be
> some really good reason to go to all the trouble to manufacture Litz wire --
> it is a pain. If wide strap were just as good or better, Litz wire would
> never have existed.)  Of course, by the time you get to HF, the
> effectiveness of litzendraht is worse compared to flat strap.  Hence it is
> only used to the MF band.  See for instance:
>
> http://www.wiretron.com/litz.html
>
> Regards,
> Bill
> "TEXAS" & WD5CVG