>Perhaps at the very end the current is zero and the voltage is
>infinite...not probable, but the range of possibility is large.
The voltage isn't infinite, of course. The "fringing-field" capacitance of
the end of the wire limits it, and the dielectric polarization of the end
insulator reduces it further. I don't know just what it is. To estimate
it you'd need E-M field modeling s/w that I don't have, although I may take
a shot at it with NEC-4, which I do have. The problem with NEC-4 is that
it can't properly model the end-insulator. Perhaps someone on the
<amps@contesting.com> list has s/w that can?
To reduce the voltage and E-field at the end of an antenna it would help to
put a ball, or something approaching a ball -- even a few small loops or a
"snarl" of wire -- on the end. Whether this would help to prevent
insulator failures, I don't know. The main reason for electrically-induced
insulator failures is probably moisture inside the insulator. I suggest
taking a lesson from the electric power utilities, and using a _string_ of
insulators at the end.
-Chuck W1HIS
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