Milt and All,
We have two issues here to solve.
1.) Quantifying the problem. We have to do that and we can
do that with a reliable valid measurement. We certainly
can't guess, and I don't want to depend on the subjective
opinion of authors who never seem to work weak signal DX.
2.) If there is a problem, making the vertical ends or
end-effect "vanish". I suspect that will involve a great
deal of work if the vertical ends actually do prove to be a
problem!
> My experience has been strictly with the Beverage antennas
terminated WITH
> sloping terminations a la Misek's book.
> They perform equally well from BC band through 40 Meters
with excellent
> directivity.
As do mine with vertical ends. My antennas also appear to
have very good directivity on 20 meters.
> >From the locations where I operate most, in SW NM and SE
AZ, many times
> while listening NE I will catch a syllable or whisper of a
call. The
> station almost always is located in the 6th or 7th
districts and when I
> switch to listen on an antenna "beaming" that direction
the signal will come
> up to S-9 or better.
As do mine with vertical ends. My Beverages actually work
better than my 40 meter three element full size Yagi up 130
ft, even though I pay no attention to 40 meter design of my
Beverages.
> I attribute this (IMHO) textbook performance to the
sloping terminations at
> BOTH ends of the Beverages.
My Beverages work quite well even on 20 meters. Should I
attribute that to the vertical ends? ;-)
I have made tests with the 8-10' piece of
> vertical wire (ie, with the Beverage element disconnected
from an elevated
> Bev feed end termination) and found it to be a VERY good
OMNI-DIRECTIONAL
> receiving antenna.
I'm not sure what you were testing. Even a perfectly
constructed horizontal wire (say a 250ft wire for 160m)
over perfectly uniform soil has more sensitivity than an
eight foot vertical feed wire running from ground up to the
middle of that wire. You would actually need a relatively
large field of symmetrical radials to have a nearly
non-rating elevated termination. It certainly cannot be
accomplished with two opposed wires!!
What is the noise floor change or sensitivity change when
you disconnect the horizontal wire or termination wire,
cancel reactance with a reasonble Q inductor, add a 450 ohms
series resistance, and go through your isolation-type
Beverage matching transformer? That would tell you the whole
story.
"Hearing signals" or why we feel something works is really
meaningless. We have to quantify the change and be sure we
are measuring what we think we are measuring.
> same length. The low level antennas ARE quieter, BUT the
signal levels are
> comparatively lower also.
The same effect occurs with small loops and skywave noise.
Even though they have virtually no directivity, the
perception is often that they are quieter. That's because
the signal and noise is less, and most receivers are very
non-linear. In order to compare antennas, the levels should
really be set the same.
Now I don't doubt for one second the ends pick up signals,
but what people somehow seem to think is the ends are the
ONLY part of the antenna responding to vertically polarized
local signals. That certainly is far from true!
The only time noise from the vertical end wires will
increase our noise floor is when the noise sensitivity of
the ends is higher than the accumulated noise from that very
long antenna wire that also responds to vertically polarized
signals.
It is easy to make some very simple measurements and
quantify the problems rather than guessing.
73 Tom
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