"Rollie" wrote in
:

You could try putting 4 ground plane elements off the SO-239
connector, I'm told they are to help with standing wave problems.

Repeating someone else's advice in this way is a detached recommendation,
and if you don't understand it, a questionable recommendation.

Attaching radials as you suggest turns the antenna into a regular ground
plane antenna. One expects the feed point impedance at resonance to be
around 35 ohms, which would result in a VSWR of 1.5 when fed directly by
50 ohm coax. Much the same outcome as feeding the coaxial dipole with 50
ohm coax.

I've never used ground plane antennas, but it wouldn't take much
effort and could be worth a try. I use the MFJ 269 antenna analyzer
when building antennas and find that the unit saves lots of time.

Sloping the radials can raise the feedpoint impedance, but I think Ed
wanted an antenna without radials for his particular application.

Owen