K2 feedline question

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K2 feedline question

Tom McCulloch
Hi all,

  Well spring is in the air and old man's fancy turns to antennas.  

  I have a K2 (s/n 1103) without the 100 watt amp and with the internal low power ATU. Unless procrastination gets the best of me again, I'd like to string up a new wire antenna this spring.

  I have a chunk of 400 ohm ladder line, which I'd like to use as the feedline and would like to know how and if I can use this with the K2/ATU.  

  Thanks

Tom WB2QDG
k2 1103
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Re: K2 feedline question

Mark J. Schreiner
Hi Thom,

One of my favorite antennas was the Double Extended Zepp, which I built at 340' long, center fed with 450 ohm ladder line and going to a balanced tuner (Johnson KW Matchbox).  It worked on all HF bands.  My tuner didn't cover 160m so I built a separate tuner for that band.  The length on each side of the feedline is essentially 0.64 wavelengths (although before I knew what the antenna was officially called I designed it at 5/8 wavelengths on each side, or 0.625, I guess not taking into account some end effects of the wire or something, but close enough anyway).  That dimension should be taken at the lowest wavelength you wanted to operate (for me it was for the DX window of the 75m band, but it still loaded and worked fine on 160m as well, being just over 5/8 wavenlength total length at 160m).

How would I do that same antenna today?  I'd probably have some sort of balun (4:1 Remote Balun from RadioWorks would be a suggestion) hanging up outside under the eaves and run coax from the ATU in the K2 to the balun and 450 ohm ladder line from there to the center fed double extended Zepp.  Are there other options?  Of course!  That is the best part about antennas!  Good luck narrowing down the field and have fun putting up the wire.

72/73,

Mark, NK8Q
K2 #4786
 

>From: [hidden email]
>Date: Fri Apr 08 15:10:13 CDT 2005
>To: [hidden email]
>Subject: [Elecraft] K2 feedline question

>Hi all,
>
>  Well spring is in the air and old man's fancy turns to antennas.  
>
>  I have a K2 (s/n 1103) without the 100 watt amp and with the internal low power ATU. Unless procrastination gets the best of me again, I'd like to string up a new wire antenna this spring.
>
>  I have a chunk of 400 ohm ladder line, which I'd like to use as the feedline and would like to know how and if I can use this with the K2/ATU.  
>
>  Thanks
>
>Tom WB2QDG
>k2 1103
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft   
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com

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RE: K2 feedline question

n6wg
In reply to this post by Tom McCulloch
Hi Tom
Yes, that is excellent feedline for multiband antennas.
Here I have a 60 ft centerfed flattop with 450 ohm window line
for feeder.  I can load this antenna on 160, 80, 40, 30, 20, 17, 15, 12 and
10m.
The feedpoint Z at the shack end changes from band to band, so I either use
a 1:1 balun or a 4:1 balun, whichever gives me the best match on a given
band.  I put one balun on ANT1 port of the ATU, and the other balun on the
ANT2
port.  With banana plugs and jacks, it only takes a moment to switch from
one
port to the other.  The ATU remembers the settings and ANT selection as you
jump from band to band.
Go for it!
73, Bob N6WG

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of [hidden email]
Sent: Friday, April 08, 2005 1:10 PM
To: [hidden email]
Subject: [Elecraft] K2 feedline question


Hi all,

  Well spring is in the air and old man's fancy turns to antennas.

  I have a K2 (s/n 1103) without the 100 watt amp and with the internal low
power ATU. Unless procrastination gets the best of me again, I'd like to
string up a new wire antenna this spring.

  I have a chunk of 400 ohm ladder line, which I'd like to use as the
feedline and would like to know how and if I can use this with the K2/ATU.

  Thanks

Tom WB2QDG
k2 1103
_______________________________________________
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Post to: [hidden email]
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_______________________________________________
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