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[TowerTalk] EF140s element tuning on F12 C4

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Subject: [TowerTalk] EF140s element tuning on F12 C4
From: n7ml@imt.net (Mike Lamb)
Date: Mon, 19 Oct 1998 15:25:46 -0600

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Hello Bob:  I am not much of an expert, but there is one thing about the
EF-340D 40 meter mono banders that I have concluded.  The linear loading
elements are aluma-weld wires.  A few times I have had problems with my
pattern going totally away (not even as good as a dipole).  I have had
some friends also tell me they have experienced the same thing.  Anyway,
I have gone up and cleaned up the clamps and jumper wires, etc and put
things back together.  When I have done that, the pattern comes back and
I start working things again.  After a few months, everthing falls apart
again.  The last time I sealed everything up with liquid tape and some
of them with 3m tape and covered the tape with plastic pvc pipe cement
that seals the tape.  We will see how long this fix job lasts now.  Here
in MT, we probably have less moisture and pollution in the air than
about any other place in the country, so I had to start agreeing with
F12 when they told me it was not necessary to seal all the linear
loading joints.  I don't believe that any more.

73/Mike, N7ML

Bob Mattaliano wrote:

>  Any F12 guru's lingering about ?  Just finished putting together a
> C4.  Can anyone comment on the expected VSWR changes for the 40M
> element as the antenna is raised.  At five feet, the EF-140S is low at
> about 6.65 MHz.  I can move the linear loading jumpers way out to
> bring the antenna up to 7.08 MHZ, BUT the jumper locations are out at
> about 35 inches not 14-18 inches as specified.  Should I just wait
> until it's "up the tower" to make the adjustments or raise the antenna
> to a higher level (10 - 15 feet ?) and try again ?  Am I just too
> close to the ground to get an accurate measurement ?  Adjusting this
> element after the antenna is on the mast looks tricky ! tks es 73, Bob
> N6RFM

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Hello Bob:&nbsp; I am not much of an expert, but there is one thing about
the EF-340D 40 meter mono banders that I have concluded.&nbsp; The linear
loading elements are aluma-weld wires.&nbsp; A few times I have had problems
with my pattern going totally away (not even as good as a dipole).&nbsp;
I have had some friends also tell me they have experienced the same thing.&nbsp;
Anyway, I have gone up and cleaned up the clamps and jumper wires, etc
and put things back together.&nbsp; When I have done that, the pattern
comes back and I start working things again.&nbsp; After a few months,
everthing falls apart again.&nbsp; The last time I sealed everything up
with liquid tape and some of them with 3m tape and covered the tape with
plastic pvc pipe cement that seals the tape.&nbsp; We will see how long
this fix job lasts now.&nbsp; Here in MT, we probably have less moisture
and pollution in the air than about any other place in the country, so
I had to start agreeing with F12 when they told me it was not necessary
to seal all the linear&nbsp; loading joints.&nbsp; I don't believe that
any more.
<P>73/Mike, N7ML
<P>Bob Mattaliano wrote:
<BLOCKQUOTE TYPE=CITE>&nbsp;<FONT SIZE=-1>Any F12 guru's lingering about
?&nbsp; Just finished putting together a C4.&nbsp; Can anyone comment on
the expected VSWR changes for the 40M element as the antenna is raised.&nbsp;
At five feet, the EF-140S is low at about 6.65 MHz.&nbsp; I can move the
linear loading jumpers way out to bring the antenna up to 7.08 MHZ, BUT
the jumper locations are out at about 35 inches not 14-18 inches as 
specified.&nbsp;
Should I just wait until it's "up the tower" to make the adjustments or
raise the antenna to a higher level (10 - 15 feet ?) and try again ?&nbsp;
Am I just too close to the ground to get an accurate measurement ?&nbsp;
Adjusting this element after the antenna is on the mast looks tricky 
!</FONT>&nbsp;<FONT SIZE=-1>tks
es 73,</FONT>&nbsp;<FONT SIZE=-1>Bob N6RFM</FONT></BLOCKQUOTE>

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