[TowerTalk] grounding radials: solid or stranded?

[Tom Rauch]

> > It has been suggested that stranded copper wire would
have little less
> > inductance and thus be more effective.
> > Is there a clear choice or is this the trade-off that
one needs to consider?

Skin effect causes the outer strand in ANY stranded wire,
even litz wire, to tend to carry nearly all the  high
frequency current. Because it is a distance from center
problem, the HF current mostly moves to the outer edges of
each stand. The air gap between the stands caused by the
radius of the stand means you have air occupying part of the
available area instead of conductor. This makes the
resistance of the wire increase.

(Litz wire has higher resistance than solid wire, but it is
useful in limited special applications where considerable
external flux cross the conductor like multilayer
transformers or inductors because it reduces eddy currents
(shorted turn effect) in the winding's conductors.)

Maybe I'm missing something, but I can't think of any
application where stranding decreases resistance or reduces
inductance in a given shape and size conductor. Can anyone
think of a case? It isn't as good in RF coils, RF leads, or
even at DC. It isn't as good in coax, it isn't as good in DC
power leads absolute diameter and material being equal.

73 Tom