"Jimmie D" wrote in message
...

"Owen Duffy" wrote in message

snip

The key to success with coaxial dipoles is
decoupling the feedline. A common configuration is to place a set of
radials, or a quarter wave choke to be effective a quarter wave below
the
bottom of the dipole lower element... this actually attempts to reduce
current below the radials, and uses the quarter wave of feedline above
the radials as part of the radiator for a little more gain.

IIRC, the ARRL had some suggestions about decoupling a coaxial dipole.

Owen

I was thinking it might be interesting to make a ferrite choke that you
can
slide on the coax to tune the antenna. You might not have to slide the
whole
choke just a bead or two that you can move a few inches.

Jimmie.

This is worth trying, too and I had thought of it. Too bad I don't what type
ferrite material I have (all junk-box recoveries, swap meet, etc). I
figured on a low probability of success, but with failure so cheap, quick
and easy -- what the heck!. ;-)