[Elecraft] Balun for KAT2

[Don Wilhelm]

Jonathan,
I may be opening a can of worms here because there are a lot of 'balun
believers' out there, but I would start with no balun at all.  It WILL work,
but there is a possibility that you may get some 'RF in the shack' - should
that happen, I would recommend an RF choke on a short section of coax (use
big coax for best efficiency).  You could use a coil of coax, but even
better is the W2DU type of balun (a bunch of ferrite cores over the coax
shield) - make your own with 12 to 20 FT-50-43 cores slipped over RG213
coax.  You need more cores at lower frequencies because it is the choking
inductance that does the job.

The baluns made by winding bifilar (or tri-filar) turns on a core can be
very lossy when used on a feedline having input impedances far away from the
25 to 300 ohm impedances that these baluns are usually designed for and they
are not very happy with reactive loads.

73,
Don Wilhelm  - Wake Forest, NC   W3FPR home page: http://www.qsl.net/w3fpr/
  QRP-L # 485   K2  SN 0020   mailto: w3fpr@arrl.net

----- Original Message -----

> I just set up an 80m dipole with ladder line (600 ohm), and may soon
become
> a believer in the open-wire feed.
>
> When using it with an ATU such as the KAT2, with low power, what is the
most
> efficient way to convert the KAT2 unbalanced output to the balanced line?
>