Well that is indeed food for thought thanks Cecil! I have never heard of
that before, but it certainly figures. I just wound another for 20m,
with abt 46 feet of wire on it, and it GDO's on approx 48 MHz ONLY!
Although the GDO coupled into the z bridge says it is resonant at 14250,
20 ohms. But the SWR is hopeless!
Now it figures....I was going to re-wind the same wire onto another
thicker whip and see what happens to the resonant freq.

Do you think it might help if I keep the close wound section to a half
wave or less, and make the remainder above and below the coil well
spaced? I know I'll need to try I guess as each antenna I try is different.
I am going to make a dummy test rig of mounting a mobile base on a piece
of scrap iron, with a simple 2-3 turn loop on the base. No coax. Then I
can GDO any antenna I screw onto it! I'm gunna solve this!
All observations appreciated!
Adrian.

Oops, almost missed this......

Cecil Moore wrote:
A length of 3/4 wavelength of wire is suggested
there.


By who?

Someone quoted ARRL handbook chapter on mobile ants.