[TowerTalk] Baluns, BN-86 et al

[Charles D. Shinn]

Hi; Many years ago I cut a pair of articles out of Ham Radio Magazine. The articles were by George Badger (callsign unknown) and modeled some hi power coax baluns with bias windings integral to the design. I used 4 or 5 of these baluns with great success. At the time I had a hombrew amp capable of excess legal...I was unable to burn up a properly constructed G Badger Balun. As I recall the baluns are made from teflon coax. I believe that researching Georges designs could save you folks some tower climbing time! (I think Georges call is W6TC?). I hope that this helps someone. de Chuck W7MAP

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From: 	jim henderson
Sent: 	Wednesday, February 19, 1997 7:47 PM
To: 	towertalk@contesting.com
Subject: 	[TowerTalk] Baluns, BN-86 et al

        Mark, my experiences with the BN-6 now lead me to discard it when I
open the antenna box. Someone with the measurement gear and math skills can
explain why it should work, but I think they just fail too often, with less
than 1200W out, and with the antenna Zi near where it should be.

        Other similar problems with other companies' baluns caused me to but
Jerry Sevick's book on the subject. You can roll your own quite easily with
that book. I also bought one of the 4:1 baluns made from his data and sold
by Amidon Associates (I think!), and use it with my big LPDA. It appears
much more robust, and I assume the same would hold true for the one you need. 

        Somewhere I lost the notes I made from taking apart the balun from
an old Telrex TB5EM. This was nothing more than some large coax (RG-213?)and
a #12 insulated wire wound into a very few turns and placed inside a
weatherproof box. There was no ferrite to fry. It gave every indication of
being a good balun and having the long life of a simple, successful design.
Just the sort of thing you want for your topmost, "hard -to-reach" antenna. 

        I never made measurements of this design, but perhaps one of our
esteemed reflectee colleagues did, or knows how to reconstruct one. 

73 de Jim, KF7E

Jim Henderson
jhenders@tdrss.wsc.nasa.gov
jhenders@zianet.com


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FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
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