RE: RF Ground Connections - Wire Type

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

When I referred to stranded wire, I was speaking generally, as I believe
the same things apply to all variants - twisted, braided, and parallel
strands, though I'm sure some are worse than others.  The stranded wire
that I tested appears to be parallel strands, where outer strands probably
remain so.  But as you said, there is probably a slight overall twist, so a
strand at 9 o'clock at one primary turn may be at 12 o'clock at the next
turn, and this would promote strand-hopping of currents. It's unclear how a
twisted but parallel construction would fare in a non-coil (i.e. ground
wire connection) application, where proximity effects are not an issue.

My comments about strands alternating between the surface and interior of
the bundle were inspired by observations of untested and presumably
inferior geometries - braid and multi-twisted-bundle construction found in
some of the heavier gauge constructions.

Regards, Gary Lau
MA, USA


Gary, DWP, all,

I just thought I'd mention that my stranded wire used in my
TT-42TC seems to be the well-mannered type in which the
outer strands remain as outer strands thoughout.  In looking
at some cheaper wire, it looks well mannered as well.  Are
you sure Gary that your wire strands plunge into the bundle
at times?  It would seem that a silver-plated stranded wire
may perform a little better than copper, because silver
conducts well even when oxidized, or so I'm told.  I don't know
if they make silver plated stranded wire with each strand plated.
It would seem to me that a stranded wire, in which the strands
remain outside would have a larger surface area than solid wire.
The wire does have a twist though, so I the current may balk
at following the strand twists due to the proximity effect or
other effects.  It may be this effect which is causing the losses.
Or maybe the RF currents remain on the outer parts of the strands,
and is not able to dip into the valleys?  Sort of similar to the way
a lot of small toroids behaves as one large one as Tesla found.
If so, this may reduce the available area of a stranded wire from
an RF point of view.  Just some thoughts.

Cheers,
John



>
> > When a strand goes from the surface of the bundle to inside the bundle,
>
>     Well mannered stranded cable has the same conductors on
>     outside thruout its length.  (Get some largish gage and
>     examine...)  Moreso with ;steel cable' as the strands are
>     stiffer.
>