I believe the advantage you are seeing with a low beverage
is the reduction of pick-up from the feeds. When you think
about it, the 8 foot vertical at each end of the higher
beverage is 1/4 wave on 10 meters and this signal dominates
the signal picked up by the beverage. At lower frequencies
the effect is lesser, but still effects f/b and f/s
signals.>>
I don't see how that could be. The radiation resistance of a
short vertical with uniform current can be closely
approximated by multiplying 1580 times height in fractions
of a wavelength squared.
A 1/100th wavelength tall vertical with uniform current has
a radiation resistance of .15 ohms.
.15 ohms radiation resistance is a tiny part of 400-600 ohms
antenna impedance.
The mechanism going on (I've never seen an improvement here
laying a Beverage on the ground) is probably the velocity
factor of the wire has decreased increasing effective
length, or he has managed to position a null on a dominant
local noise source.
What everyone seems to ignore is the entire Beverage from
end-to-end receives vertically polarized signals. It is very
unlikely that two mismatched 1/100th WL long verticals would
ever inject meaningful noise or unwanted signal to a wire 1
or 2 wl long that the 1-2 wl long wire wouldn't already be
receiving.
If the ends had enough sensitivity to change noise level,
the pattern would be terrible. It all comes back to antenna
pattern.
73 Tom
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