On Jun 21, 9:36 pm, John Smith I wrote:


Now there is no reason for anyone not to experiment a bit ... the
fixture is far from ideal, your improvements are welcome--it is quick
and dirty to construct!

Regards,
JS


Hummm, I would use a slightly wider spacing with the
loading coil wires.. Too tightly wound.. I assume the
wire is enameled... The problem with this, is your
lower coil is the same diameter as the center load.
But, your lower coil is actually the more efficient
of two, being it's wider spaced. You are stunting
your upper coil with too close together windings.
I actually believe the current distribution would be
slightly better with all center loading, than with the
mix of two coils, one being basically a base load.
I would also clip those "mast" wires where they
don't run along side of that coil. Thats not good.
Like I say, I've already tried all this with helical
glass whips combined with larger hi-Q coils.

I don't use it anymore. Now all my loading is one
center loading coil.
I once combined the glass stick helical windings
with the larger lumped coil. But came to the conclusion
it was a bad idea because the narrow helical windings
on mine were more lossy than the larger coil.
But on yours, all windings are the same size dia..
So it really doesn't matter, except as far as current
distribution. My gut instinct is that you would force
more current up the mast , using only the upper
center loading coil. This is what you should test.
Use equal whip and stinger sizes, and compare
the "split loading", with a loosely wound all
center coil. Not tight wound like you have.
Have about at least a wires width of space between the
windings.
If the all center loaded antenna didn't win, I'd be kinda
surprised. The way I see it, if you share loading
locations, the current distribution will also share
the two locations.. IE: you should have more current
lower on the mast with the split coils, than with
only a center coil. To me, this should offset any
advantage of less total turns being needed, from
using partly a base load. All center loading should
need a few extra turns to tune vs the split setup
I would think, but it's not enough to hurt you much.
MK