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>

Braided wire is used in lightening protection applications because it's
flexible and much easier to use.  A lightning-conductor only needs to be a
better conductor than your house or whatever else it is that you are
protecting, so it needn't have the lowest possible impedance.

Stranded conductors are also used in audio applications because solid
conductors would be just too stiff.  True audio snobs will tell you that
Litz wire is the best conductor to use, though I seriously doubt that
there's any measurable, much less audible difference between
solid/stranded/Litz at audio frequencies.

Where have you heard that stranded/braided wire outperforms solid?

Gary Lau
MA, USA



>>Original poster: "Mccauley, Daniel H by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>


	>>I'm going to have to disagree with your assessment.  For high
>>voltage transients, stranded or braided wire outperforms solid wire in all
>>instances.  This is the primary reason you use braided wire for lightning
>>protection in house security systems etc...  Another example is the use of
>>stranded wire vs. solid in audio applications.  
>>
>>	Dan




> My recent measurements of conductor AC resistance confirm that stranded
> wire is a POOR choice.  While one should strive for a high surface area,
> this only applies to solid conductors.  RF currents want to travel only on
> the outermost surface - they will not travel on strands inside the bundle.
> When a strand goes from the surface of the bundle to inside the bundle,
> the
> current will try to hop to an outer strand, through whatever surface
> oxides
> might be in its path.  I did not compare finely stranded conductors with
> coarsely stranded conductors, but I would speculate that a coarsely
> stranded conductor might have a lower AC resistance, as it's a closer
> approximation to a solid conductor.
> 
> Steel cable, solid or otherwise, would be a very poor conductor due to the
> inherently higher resistance of steel compared to copper.
> 
> Since heavy gauge solid wire is inflexible and not practical for a cable,
> I
> would recommend a copper ribbon for the best possible conductor.  Home
> Depot sells copper roof flashing by the foot, you would have to cut it
> into
> strips and solder them together.
> 
> Now to the practical aspects.  An RF ground, good or bad, will have
> virtually no effect on the coil's performance.  Several list members have
> accidentally forgotten to connect their secondary base to a ground of any
> sort, and there was NO impact on performance!  The real reason for using a
> ground has more to do with preventing RF interference and HV RF nasties
> from entering your house wiring.
> 
> Gary Lau
> MA, USA