[TowerTalk] Coax STubs for SO2R

Jim Brown jim at audiosystemsgroup.com
Mon Sep 7 23:22:02 EDT 2015

On Mon,9/7/2015 3:36 PM, Mike Smith VE9AA wrote:
> I've seen the K2TR stubs, K1TTT page and have recently bought the FB book by W2VJN
> Today, for a change, I had a little spare time so built 2 stubs, but lets
> just concentrate on one.
> It was supposed to be for the 40m transmitter.
> I roughed out the length, attached a T and my antenna switch (a la VA2UP
> method) (which I'll only use for stubs, trimmed it with my AA-230pro
> and when it's inline (parallel to my primary antenna switch) I see no
> difference at all on 20m or 15m on my 2nd receiver when the stub is in or
> out of line

The link below is to a piece I wrote on exactly this topic for the most 
recent NCJ (National Contest Journal).


It is in response to an earlier piece by W2VJN, in which I found some 
important errors.  After batting it around with the "brain trust" (N6BV, 
N0AX, AE6TY, AC6LA, and George), I wrote the piece. Most of George's 
book is excellent, and I've found those parts quite useful.

I suggest that you study it until you understand all of the fundamental 
concepts. Depending on your technical background, you may also need to 
crack the ARRL Antenna Book on the topic of Transmission Lines. :)  You 
might also find k9yc.com/Coax-Stubs.pdf helpful.

73, Jim K9YC

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