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Subject: C4S
Author: Natan Huffman <force12e@lightlink.com>
Date: 02-Apr-2000 14:23:15


George,
 
First thing to do is to verify that the feedline and all its connectors are proper.  Do this by putting a dummy load at the end of the feedline that is used for the 40 meter part of the C4.  If you see other than a 1:1 VSWR, the antenna is not the problem.
 
What are you using to measure the VSWR?  If it is an analyzer, particularly the MFJ 259, are the VSWR readings nearly
the same on the analyzer as on the VSWR meter in your radio?
 
A 5:1 VSWR indicates the antenna assembly needs to be reviewed.  Look for the correct element lengths and the correct attachment of the loading wires.  If moving the tuning jumper produces no change in VSWR, you probably have an assembly issue relating to these wires.  Compare your assembly to the manual and to the photographs on www.qth.com/force12/ under TECH TIPS.
 
Be sure there is not a jumper shorting the two halves of the 40 meter element.
 
Did you install the coil across the center of the 40 meter element.
 
If you suspect the balun, replace it with a RF choke of 8 turns of 50 ohm coaxial cable in a 10" loop.  This type of RF choke is just as effective as a balun and a lot cheaper too.  Your manual gives you instructions about this choke.
 
Is there another antenna, wire or aluminum close by?
 
Let me know how you do.
 
Natan W6XR
Force12 East
Ithaca, NY
FN12sk
----- Original Message -----
Sent: Sunday, April 02, 2000 11:06 AM
Subject: [Force 12 Talk] C4S



I have been up and down my tower like a yo yo and can not get the swr down on 40 .Have moved the tuners in and out ,but swr still 5 to 1..Changed the feed line to the Wireman 1:1 balun and no help there,not really sure what the distance should be on the phone part of the band,had it at 18 in. and in to 5 in..The only other thought I had was maybe the new Balun could be bad? The other bands are great,any thoughts??


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This Thread
  Date   Author  
* 02-Apr-2000 Natan Huffman
02-Apr-2000 John Langdon
02-Apr-2000 GEORGE DAWSON
This Author (Apr-2000)
  Subject   Date  
40 meter N elements & 72 ohm 08-Apr-2000
* C4S 02-Apr-2000
De-bugging Presentation 16-Apr-2000
Debugging an antenna system 15-Apr-2000
F12 C4SXL .. Tuning .. 15-Apr-2000
nuts 05-Apr-2000
Recommendations 03-Apr-2000