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

Pi*D is circumference, or Pi2R.

1" pipe exceeds the surface area of 3" strap. As totally impractical as
copper pipe would be as a bonding conductor in almost any application,
it
would make an excellent RF ground connection on shore facilities where
it
would offer several times the surface area of a solid ground rod half
it's
diameter. Copper pipe is commonly filled with conductive salts which
leech
through holes in the pipe to maintain high conductivity in ground rod
installations.

Jack my boy you need to go back to school and refresh your geometry.

Pi*D is circumfrence This is true. Now what is the outside surface
area for one inch of length of 1" dia copper pipe?
Lets see 3.1416*1"=3.1416 3.1416*1" length = 3.1416 Square Inches.


Now lets look at 3" copper foil.....ok for Inch of length
we have 3.0 inches square inches of surface area on the front
side and 3.0 square inches of surface area on the back side.
That makes a total of 6 Square Inches of surface area per 1"
of length. We will ignore the thickness of the foil, just because
it isn't significant for the terms we are discussion here.

Now which has more surface area per linear inch?

3.1416 Square Inches for the copper tubing........

or

6 square Inches for the 3" foil........

Hmmmmmmm, wonder what could be the answer.........

If you like, you could think of the copper tubing as being flattened
into a bar and measure it again and it still wouldn't approch a 3" foil
for surface area.

You don't get to include the inside surface area of the tubing, because
RF flows on the outside surface only, but even if you did, you would
still come up a bit short on surface area when compared to 3" copper
foil.

C'mon ol' salt, you should know the inside of copper pipe is electrically
identical to both sides of copper strap when a bonding connection is made to
either. Skin effect of electrical current is felt equally on both in _that_
condition. Electromagnetic induction on a material from one outside
direction sees skin effect on the outside surface only of a closed
structure, cabinet, pipe, etc. But we are not talking about EMF's. We are
talking about a bonded connection that has RF voltages, and during tuning
applications, RF current applied directly to the conductor. Respectfully, my
geometry and description of the conductor skin-effect condition are both
correct, and 1" pipe exceeds the surface area of 3" strap.

Best regards,

Jack Painter
Virginia Beach, Va