michel wrote:
That is some clear information!! The 5/8 wave version needs a shorted stub
as well?

After my first cup of coffee, I canceled my previous
posting. The matching method I described works well
for balanced dipoles but is probably not applicable
to monopoles with no ground plane because the current
in the other leg of the series matching section has
no place to flow in a J-Pole configuration. So a 0.2WL
matching stub is not a good feed design for a 5/8WL
monopole and will generate common-mode problems unless
there is a ground plane into which the current can flow.
Best to stick with the standard 1/2WL J-Pole design. I
apologize for my fuzzy thinking - it made sense until
I woke up. And it would work for a 5/8WL monopole if
it already had ground plane radials.
--
73, Cecil http://www.w5dxp.com