[TowerTalk] Measuring Stubs

[NPAlex at aol.com]

Tom,
My experience says that measuring a stub is best when the expected R=0,  
Therefore you want to leave the cable open for quarter wave length as it  reflects 
Low Z at the feed end.  The same length coax as the 1/4 wave on  40, will be 
a 1/2 wave on 20m.  In this case the termination should be a  short as the 
half wave transfers its termination Z..    You can  short the cable to begin with 
if you like, but usually 1/4 wave cables shorted  have a less pronounced peak 
R vs the rather sharp null when open  circuited.  
 
Norm W4QN
 
===============================================================
Hi  all

I just got a MFJ 259B and trying to set up some stubs.

On 40,  there is a quarter wave stub, shorted on the end.
On 20, there is a stub the  same length, only open.

On the 40 meter stub, do I just tune it for a  RX=0, then short the end after 
I measure it, or short the end and measure it  that way?

And on 20, do I short the end, as in a 1/2 wave and measure it  that way? 
Thanks and 73
Tom W7WHY
 



************************************** See what's free at http://www.aol.com.