"Bruce in Alaska" wrote
"Jack Painter" wrote:

Meindert, water is not a good conductor, with average tap water having
100,000 ohms resistance across 1 meter of 15mm plastic pipe filled with
water. Even at RF frequencies, where skin effect is most pronounced, a
bonded connection made equally to both inside and outside of a copper
pipe
should exhibit skin effect throughout most of the entire cross section
of
the copper pipe. This is because the wall thickness of the copper pipe
is
not materially different from copper strap.

Example:

For copper tubing used as a inductor in antenna tuners:

coil length
R= ---------------------------------------
conductivity *skindepth*2pi*coil radius

Now, applying voltage to the outer surface only of copper tubing with
closed
ends, whether by EMF attachment or bonded connection to the outside
only,
would exhibit surface-only skin effect similar to if a faraday cage was
constructed of the same copper strap we are talking about. The outside
surface would carry most current. But if the voltage connection was
bonded
to both inside and outside of an opening of the faraday box or the
copper
tubing, then current via skin effect would be nearly constant on the
inside
and outside surfaces of the box, defeating the faraday effect. The
condition I originally described, that of a bonded connection, applies
voltage equally and carries current equally on the entire skin of the
conductor, inside and out, 360 degrees, as efficiently as a piece of
copper
strap of similar cross section.

Best regards,

Jack Painter
Virginia Beach, Va

Jeeezzz Louise Jack, where did you learn all this BS that your spreading.

But if the voltage connection was bonded
to both inside and outside of an opening of the faraday box or the
copper
tubing, then current via skin effect would be nearly constant on the
inside
and outside surfaces of the box, defeating the faraday effect.

Please explain how one "BONDS" a connection to only the inside of a
copper pipe. All of the Physic Professors of the World would really
like to know. Are you saying that if one made a "RF Connection",
to only the inside of a copper tube, that no RF would flow on the
outside of the tube? That is just plain wrong, and a stupid statement
on it's face.

ok, enough of this BS, CFR!!! (Call for Reference) Let's see if old
Jack can actually come up with some documentation that RF flows on the
inside of a connected copper tube or pipe. Lets go for some Peer
Reviewed Documentation here, the straight, No ****, Textbook, kind
of documentation, written by some really Qualified Physics Phd's.

Hmmmm, all the PhdEE's that I asked, just laughed and ask how the
weather and fishing was.........

Bruce, you're making a totally off the wall argument now, with opposite
assumptions that were never asserted or offered by any of the posters to
this thread. Taking your questions literally as you phrased them would
generate a laugh by all, indeed. If a laugh was your intention, we'll all
have a good one. But I doubt that you are confused about skin effect, or why
a faraday cage works, and specifically what would defeat it's protection
(ie: an opening). So if you seriously think that for instance, a c-clamp
applied across an open end of thin walled copper tubing, contacting the
inner and outer wall in it's grip, would apply voltage differently to the
inside versus the outside of this tubing, then it will be easy to explain
your error in thinking. And since I did not make a joke of your obvious
geometry and math errors in determining the surface area of an object, one
which you continue to be confused about, I would suggest that we either: end
the thread if you do not desire pleasant and professional discussion, or,
omitting the snide comments that do not reflect well on the group or it's
interested participants.

Respectfully,

Jack Painter
Virginia Beach, Va