[TowerTalk] KLM Balun Phasing Marks

[Dave Hachadorian]

On Wed, 11 Oct 2000 19:34:00 +0100 Bill Tippett <btippett@alum.mit.edu>
writes:

>  I also have an old 
> KLM
> Balun circa 1980's which I can use as a substitute if I can 
> determine the
> proper phasing connection.  Note...both baluns are the same 
> construction with
> a PVC tube and end caps...not the old old (skinny) baluns from the 
> 1970's.

Here is a repost of a technique suggested by N2IC
-----------------------------------------------
I have a pair of KT34XA's stacked on one of my towers.  I have found that
the only sure-fire way to make sure that the phase is the same on the 2
baluns is to measure it.  Here's how I did it ...

- Run a little RF (< 1 watt) into both baluns simultaneously, using a
T-connector.
- Attach the balun leads in series.
- Using an RF voltmeter or oscilloscope, measure the output voltage.
- Flip the leads on one of the baluns around
- Re-measure the output voltage.

You will see a large difference in the output voltage - indicating in one
configuration you had the baluns in-phase, and the other configuration
out-of-phase.  Now put a mark on each balun indicating the phasing.

73,
Steve, N2IC/0
-----------------------------------------------------------

>        Which brings me to my next question!  Has anyone disassembled
one of
>these baluns?  It appears you can do so by undoing the locknut on the
coax
>connector and knocking the end cap off.  This may be the easiest way to
>check for proper phase of the two baluns but I would like to hear from
anyone
>who may have done this before I start tearing both apart.

The cap is glued on there pretty tightly, but it can be dislodged by
wedging a screwdriver between the cap and the pvc body, and whacking the
screwdriver with a hammer. You may do some damage to the pvc, but you
can glue it all together again later. It's a basket case anyway, right?

Dave Hachadorian, K6LL
Yuma, AZ
K6LL@juno.com


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