There have been several articles, at least one in NCJ and one military related
about absorption by trees. Deciduous seem to be the worse, and I would vouch
for a noticeable difference when a tree is in full leaf or not.
Two wires between the trees does seem like a better option and I would fold
them towards each other moxon style. Rumor has it this will help f/b a bit.
Wouldn't it be nice if we all had wide open salt marshes for our verticals? ;o)
Julius Fazekas
N2WN
Tennessee Contest Group
http://www.k4ro.net/tcg/index.html
http://groups.google.com/group/tcg1?hl=en
Tennessee QSO Party
http://www.tnqp.org/
Elecraft K2/100 #4455
Elecraft K3/100 #366
Elecraft K3/100 #1875
--- On Tue, 11/3/09, DAVID CUTHBERT <telegrapher9@gmail.com> wrote:
> From: DAVID CUTHBERT <telegrapher9@gmail.com>
> Subject: Re: Topband: Improve efficiency?
> To: "Lew Sayre" <w7ew@arrl.net>
> Cc: topband@contesting.com
> Date: Tuesday, November 3, 2009, 4:38 AM
> Lew,
>
> I'm thinking that the close spacing between each tree and
> each vertical is
> absorbing a significant amount of signal. How much I don't
> know.
>
> If it is clear between the two trees I could see stringing
> a rope between
> the two trees and putting up an Inverted-L or a T right
> between the trees.
> The antenna now has 90' to the nearest tree.
>
> Dave WX7G
>
> On Mon, Nov 2, 2009 at 11:41 PM, Lew Sayre <w7ew@arrl.net>
> wrote:
>
> > TopBanders,
> > While trying to attract SV3RF's attention
> last night on Top band it
> > occurred to me that I need more efficiency in my Tx
> system.
> > What I have is two fir trees, each about 110' tall and
> 189' apart. I have 2
> > 12GA copper stranded wires going up and over the top
> of
> > each tree with about 18' of wire going from vertical
> to horozontal as it
> > goes over the top. I have 60 1/4 wave radials
> under each wire
> > on the rocky ground that runs through essentially
> forest which surrounds
> > these two trees with a bunch of other fir trees. I
> layed down
> > radials under each wire until I saw no further change
> in the SWR in each
> > vertical wire. The SWR individually for each
> wire is about 1:1.5 at 1830
> > so I've used no matching system.
> > I have a COMTEK Box that I use where I do
> see some F/B when working
> > Oceania and EU...but not much..pretty subjective when
> the max gain might be
> > 3 dB.
> > I also suspect that all the fool trees
> around me knock down the signal
> > some...but no real idea of how much.
> > Question: You think changing from the inverted L
> configuration to an angled
> > wire at about 60 degrees for the full 128' length
> would make any
> > improvement
> > in efficiency? Would angling the wire toward EU
> help or hurt the signal in
> > that direction?
> > When the tower fairy comes
> some day and erects a 190' tower in my
> > woods, then maybe I can make a K3LR type array..but
> until then any
> > suggestions for the current lash-up to make it radiate
> better?
> > 73 and I remain,
> > Lew W7EW/W7AT
> > _______________________________________________
> > 160 meters is a serious band, it should be treated
> with respect. - TF4M
> >
> _______________________________________________
> 160 meters is a serious band, it should be treated with
> respect. - TF4M
>
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
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