Re: RF Ground Connections - Wire Type

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

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

Tesla list wrote:

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

	Two Words:
		Litz Wire
	noted for its low RF loss.

> 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.

 
> Steel cable, solid or otherwise, would be a very poor conductor due to the
> inherently higher resistance of steel compared to copper.
	The surface are governs.


> 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.
	concur.


> 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.
	...and i believe some have reported there is a difference.

	A good collection of which report which would be
	instructive.  I suspect that high powers benefit from
	grounds.  I suspect that many 'ungrounded' coils are
	_really_ grounded via corona, or other leakage, at the
	low end....
	But that's just speculation.... so far....

	best
	dwp

...the net of a million lies...
	Vernor Vinge
There are Many Web Sites which Say Many Things.
	-me