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[TowerTalk] bad coax? and EF-240 tuning

To: <towertalk@contesting.com>
Subject: [TowerTalk] bad coax? and EF-240 tuning
From: pramey@smtplink.ram.com (pramey@smtplink.ram.com)
Date: Wed, 15 Oct 97 15:45:40 EST
     I have a C4-XL/D  on 40M it is the same antenna.
     Are you using a balum?
     You tune the center freq by adjusting the liner-loading wires.  The 
     hairpin match is adjusted for a 50 ohm match.  I dipped my antenna at 
     the freq that I wanted for a center and then used the hairpin for a 50 
     ohm match.  
     
     Paul 
     WG0G/W2


______________________________ Reply Separator _________________________________
Subject: [TowerTalk] bad coax? and EF-240 tuning
Author:  leewells@lexmark.com at SMTPLINK-rammob
To: <towertalk@contesting.com>
Date:    10/15/97 2:06 PM


I'm having a little trouble getting the elements for my Force-12 EF-240 
tuned up properly.  I hauled the driver element up the tower yesterday 
to check out the resonant frequency, and found two suprises...the
resonant freq was much higher than expected (7.300) , and the SWR was 2:1 at the
dip.  
     
So I lowered the element back to ground level, checked it again and the 
resonant freq had shifted up by about 50 Khz (sounds okay).  But then
I changed feedlines (RG-8X), and the freq was down to 7.115 (closer to expected)
but the SWR is still around 2:1.
     
The original coax is 9913F (about 150-160 feet), its brand new, never 
been on the air or outside.  The second coax is some old RG-8X that is 
about 40-50 feet long.
     
A couple questions:
     
1)  Should the 40 Meter element have a dip of 1:1?????  If so I've got some 
work to do on that element.
     
2)  How do I figure out if my coax is bad???  Would a bad connector installation
cause what I'm seeing (maybe the dielectric got too warm and the center 
conductor
     
migrated too close to the shield?)
     
     
Thanks & 73's
--Lee - KT4ZX
Georgetown, KY
     
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