Hi Ed,
FWIW, I had a linear loaded elevated vertical for a few years, and then
switched to a 60 foot base loaded (8" air core, made of 10 gauge wire)
also elevated and my "impression" is that the base loaded vertical is
far superior. Having said that, there are some differences, in that the
vertical portion is longer on the latter vertical, propagation on 160 in
the last few years has been better....
Another thought, why not use top loading instead?
73,
Bob/AA6VB
-----Original Message-----
From: topband-bounces@contesting.com
[mailto:topband-bounces@contesting.com] On Behalf Of Edward Swynar
Sent: Tuesday, February 23, 2010 7:19 AM
To: topband@contesting.com
Subject: Topband: "Linear Loading" & 160-Meters
Good Day All,
I've seen references in ON4UN's book regarding the use of "linear
loading"
to compensate for short physical vertical antenna heights...and I recall
reading somewhere once where Bill Orr (W6SAI) claimed that a 1/4-wave
inverted "L" may be bent by as much as 2/3 of its "natural" length
before
there's any really significant negative impact upon the antenna's
ability to
effectively radiate a good low-angled signal...
Combining these two notions together, has anyone reading this ever tried
a
linear loaded Bobtail array for 160, or even a linear loaded 2-element
half
square, for the band...?
With the Bobtail, I'm thinking here of having, say, a vertical height of
some 60', with the remaining "balance" of each vertical leg (70', or so)
being made-up of back-and-forth parallel wires, physically elevated
above
real earth by posts some 3' - 4', or so, in height.
Naturally, I wouldn't try this until the weather breaks here in southern
Ontario!
One advantage with a Bobtail, surely, would be THREE vertical
elements---but
at the cost of just ONE radial field! But would linear loading steal
away
these benefits through inefficiency...?
Hmmm...! Food for thought. I, for one, have NEVER seen any reference
anywhere, in any publication, along this line...have you?
~73!~ de Eddy VE3CUI - VE3XZ
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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