----- Original Message -----
From: Steve M <wmoorejr@cox.net>
To: Steve Thompson <g8gsq@qsl.net>; <amps@contesting.com>
Sent: 04 October 2002 22:05
Subject: Re: [Amps] skin effect
> > > Steve,
> > >
> > > The advantage of regular stranded wire is flexability.
> > > Litz wire is a special type of stranded wire that is used to reduce
skin
> > > effect.
**Ok thanks.
> > The longwave guys certainly love it - the key point is that the strands
> >are insulated from each other.
**Insulated---ok, this is starting to make some sense.
> >
> > A lot of stranded wire is multiple cores of tinned copper - skin effect
> > means that, at hf upwards, the rf current flows in the tin plating which
> >is relatively lossy. You'd need to be sure that people were comparing
like
> > wires.
**I'm not sure what some of them are comparing. hi hi **Ok on
the tin being lossier than copper, but tin or copper regular stranded [not
litz] has no advantage as to skin effect over same gauge solid tin or
copper? Is this right?
>
I believe so, but I'm wide open to correction. I think there are effects to
consider with multi-strand insulated wire, much the same as with close wound
coils. I can't recall the detail, but current flowing in close adjacent
wires tends to force the current into the centre of the wire, reducing the
cross section of current flow and so increasing the loss. Somewhere I have
some info. which relates to the effect in multi turn rx loop antennas.
Once, as an experiment, I changed a coil in a 8877 6m tank circuit from 3/8"
copper tube to (I think) 7x1mm enamelled wires twisted together. In simple
terms, there was more cross section for the rf current but in practice the
coil burnt out in a big way after a minute or so key down.
Steve
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