On Tue, 28 Jun 2005 16:18:56 -0700, Frank Gilliland
wrote:

Yep. And I should add that 18' of coax is recommended not because of
it's propogation characteristics -inside- the coax, but because of
it's velocity factor on the -outside- of the shield which is nearly 1.
IOW, when the shield of an 18' length of coax is grounded only at one
end, that ground will be reflected at the other end of the coax. At
least that's the theory. In practical use it's not perfect, but it's
still better than a fully ungrounded radio or antenna
*****

your reasoning does not pass the common sense rule.

if 18 feet is special because the velocity factor outside the shield
is nearly 1, then no other length has a velocity factor of nearly 1?
What would cause the outside velocity factor to change?

Beisdes I really don't care to rehash this topic to much more. Been
there, done that and don't care to review it right now.

james