"Jeff Liebermann" wrote in message
...

I'm not sure of the frequency of your J-pole. The inductance of about
6 cm of #12AWG solid wire is about 0.05 uH.
http://www.consultrsr.com/resources/eis/induct5.htm
To resonate at 146Mhz, that would be about 24 pF. 50 Mhz would be
about 200 pf.

That's enlightening.

I need to admit that no such science was applied. I just tried small caps
from my stash to see what would happen. When something good happened, I
remembered it for next time.

The j-pole that seems to benefit most is the 2m version, which I've built
the most of. Perhaps we're not dealing with just the inductance of that 6
cm of wire. There could be some residual inductance in the rest of the
antenna which is being brought to resonance. Maybe when my element lengths
are not optimal, some inductance would be found there. Not sure why the
residual reactance would always be inductive. The first time I add a cap
and it gets worse, then I'll know it isn't so.

Maybe I should experiment with varying the spacing across the stub and see
what that does, with and without a cap.

"Sal"