Tuning 88' with KX1 autotuner?

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Tuning 88' with KX1 autotuner?

Jim AB3CV
Just wondering if anyone has tried their KX1 with the autotuner on an 88' doublet with a windowline feed?

I'm getting ready to erect an 88 footer in my backyard. My height will be around 35ft and I'll have 80 feet or so of ladderline.

How did you do the coupling of the ladderline to the kx1, any feedline length issues and how did it load up?

tnx
jtm (drooling over a kx1)
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Re: Tuning 88' with KX1 autotuner?

Rick Dettinger-2
Jim  -  That is my antenna, currently installed as an inverted vee with
center at 40 feet.  I have about 80 feet of window line.  I just tried it
with my KX1 using an Elecraft 4:1 balun.  [Usually, I use an outboard Z
match tuner (NORCAL)].  On 40 meters, I got an SWR reading of 2.3  while 30
and 20 meters were 1.1 and 1.0 respectively.  I could probably get the SWR
on 40 meters down by changing the feed line length.  Of course, this would
change the other bands.  The balanced antennas are harder to match than the
end fed wires recommended in the KX1 ATU manual.  I get close to 1.0 on all
3 bands  with an end fed 80 foot wire sloping up to 30 feet and a 33 foot
wire laid on the ground.  I highly recommend the KX1 for portable use.
   73 - Rick - K7MW ----- Original Message -----
From: "Jim Miller" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, February 20, 2005 3:21 PM
Subject: [Elecraft] Tuning 88' with KX1 autotuner?


Just wondering if anyone has tried their KX1 with the autotuner on an 88'
doublet with a windowline feed?

I'm getting ready to erect an 88 footer in my backyard. My height will be
around 35ft and I'll have 80 feet or so of ladderline.

How did you do the coupling of the ladderline to the kx1, any feedline
length issues and how did it load up?

tnx
jtm (drooling over a kx1)
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Re: Tuning 88' with KX1 autotuner?

Vic K2VCO
Rick Dettinger wrote:

>  I could probably get the SWR
> on 40 meters down by changing the feed line length.  Of course, this would
> change the other bands.  

Easier than trimming (and maybe lengthening!) window line is the following:
wrap a piece of aluminum foil about 1 foot (30 cm) wide around the ladder line.
  Slide it around on the line until you find a place where all the bands are
within matching range.  You can use more than one piece of foil if it helps.

You have made a capacitor whose effect on the impedance will be greater as you
approach a voltage loop for a particular band.  I have done this successfully
with a few hundred watts -- it probably would not be good for very QRO
situations where the voltage loops can reach thousands of volts, but it should
be safe for your KX1 :-)

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco

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Re: Tuning 88' with KX1 autotuner?

Stuart Rohre
In reply to this post by Jim AB3CV
Any time you have trouble loading a given balanced line, simply try adding 5
or 10 feet of line to the feeder and it should tune.  You are moving the SWR
node along the line to give the tuner a more favorable voltage situation.

Stuart
K5KVH


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