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Re: Topband: Restistance of wire

To: Topband <>
Subject: Re: Topband: Restistance of wire
From: Mike Waters <>
Date: Wed, 3 Dec 2014 15:16:03 -0600
List-post: <">>
I didn't realize that what I mentioned was on Owen's new site.

"For example, a 0.5mm diameter mild steel wire has skin depth of 0.006mm at
1.8MHz, and as explained at ,
Rrf/Rdc is approximately diameter/(4*δ), so 0.5/(4*0.006)=21... RF
resistance is 21 times DC.

"If you calculate the case for the same size copper, it is 12% of the steel
case... it is not intuitive due to the complexity that high R increases
skin depth (and therefore reduces the effect of the higher resistance
material to some extent), high permeability decreases skin depth... no

"Mostly people use conductors that are not so simple to calculate."

73, Mike

On Wed, Dec 3, 2014 at 2:20 PM, Mike Waters <> wrote:

> One thing that would affect RF conductor resistance is the paramagnetic
> properties of the conductor. If, for example, it was bare iron or magnetic
> steel wire, then we would have eddy current losses. And those losses could
> very well be much larger than the ohmic losses measured at DC.
> The wire should be non-magnetic; if it IS magnetic, then it needs to be
> plated with a sufficiently thick non-magnetic material or the losses could
> be quite high. Owen Duffy (ex- VK1OD) nicely explained this some time ago
> on his old web site. (His new site is
> Exactly how magnetic wire would affect a Beverage antenna, I'll leave for
> others to expound on.  Or measure. :-)
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