Hi Larry,
I wonder if you had both antennas up at the same time and
did A B comparisons, or if this is by feeling or memory?
YMMV is certainly the concept in play here. I have run
Beverages from 180 foot long all the way out to 1100+ feet
in length. I can see definite improvement for every
additional foot of length.>>
Are you really saying for every foot added you saw an actual
improvement? I barely notice a difference between 600 feet
and 800 feet and almost never see a difference between 800
feet and 1000 feet when comparing two Beverages that are in
place at the very same time.
The observed difference in usable performance between a 550
footer and an 1100 footer is about the same as the
difference between a 500 footer and the TX vertical. >>
Well, in my case a 500 foot Beverage is about 6-10dB better
S/N than my transmit vertical and I am in a very quiet
location. Assuming 6dB, are you really saying doubling the
length gives you an additional 6dB S/N ratio? The perfect
case is only 3dB S/N change for double the length, and this
assumes a perfect situation that we really can't obtain in
the real world.
800 footers are very much inferior to the 1100 footers.
Proper terminations are required for optimum performance in
EVERY case here. I could run out to 2000 feet but haven't
because I can hear so much more than I can work with the
1100 footers, I don't want to be even more depressed!>>
Did you have them all up at the same time? I'm having a
difficult time understanding why a ~ 1/3 length decrease
translates to "very much inferior". I spend a lot of time
comparing multiple systems at the same time and have
discarded inferior antennas. The only substantial change I
see is with broadside pairs that are 350-400 feet apart.
Length, once over about 700 feet or so, just doesn't do
much.
In an ideal perfect-phase lossless world a 1000 footer would
be 3dB better than a 500 footer, and it would take 2000 feet
to gain 6dB over the original 500 foot antenna. But that
would require zero current loss in the Beverage and the
unterminated Beverage would have zero dB F/B ratio. We know
that can't happen in a passive antenna because that means we
have a lossless non-radiating transmission line...not an
antenna! Otherwise the antenna has current taper with
length, and doubling length cannot add 3dB gain. It is an
impossible situation unless we use an antenna with
distributed amplifiers and phase compensation.
73 Tom
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