On Mon, 26 Nov 2007 11:06:29 -0800 (PST), art
wrote:

At what distance does the coax
have to travel such that current on the outside does not exist?

Hi Arthur,

According to Brown, Lewis, and Epstein's work, the currents absorbed
by ground dissipate radial wire current (what is flowing on the
exterior of a coax) in a very short interval.

However, just where it "does not exist" is like the problem you have
with skin effect. The current diminishes asymptotically towards zero,
but most would agree that the practical current is gone within less
than a quarter wave length. The convergence with the asymptote could
be described to be infinitely far away - especially when the current
levels induced in far receiver antennas is so miniscule in comparison
to the diminished radial currents (4,5 or 6 orders of magnitude?).

73's
Richard Clark, KB7QHC