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[TowerTalk] Collins Coaxial Balun

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Subject: [TowerTalk] Collins Coaxial Balun
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Date: Tue, 18 Nov 1997 18:52:31 -0800
>      Since I am taking the 402BA down to rebuild, I might as well replace
>      the coax (Preventative measure). The Collins Coaxial balun interests
>      me. Not having a CQ library, can anyone provide more info on this.
>         Thanks, Dick, W1KSZ
I use the version from Mar '80 HR for a 50ohm 1:1 balun as follows:

        RG 8X  50" long
        #12 insulated wire  50" long (I use the plastic covered stranded)

        The coax and wire are COUNTER wound into a coil of 4.5" dia to make a 3
1/2 turn coil of each piece.  This means that the coax is wound
clockwise and the wire counter clockwise with it.  The #12 wire attaches
to the shield of the coax at one end and then attaches to the center
conductor of the coax at the other end.  I tape the whole thing
Put a coax connector on the same end that the #12 wire attaches to the
shield.  The antenna (balanced load) connects at the other end to the
coax shield for one line and  the center conductor+#12 wire junction for
the other line.  A picture is better.  I hope this helps.  The artcle
was excellent,  I have successfully used these things since 1980 under
high power and SWR conditions.

My power tests and SWR test show it flat to about 35MHz.  I check my
recent one with the MFJ analyzer with similar results and I also noted a
self resonant frequency around 47MHz.  I use it on dipoles and my Wilson
System 1 through 10 meters.

Good luck..  George W1ZT

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