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TopBand: Matching transformmers

To: <topband@contesting.com>
Subject: TopBand: Matching transformmers
From: tree@lady.axian.com (Larry Tyree)
Date: Wed, 11 Sep 1996 11:31:08 -0700 (PDT)
I always make my own transformmers for beverages.  

Take three small wires about 5 feet long and twist them together.  
Then wind them on your ferritte core.  Then put the three windings 
in series (make sure you don't connect the same ends of any two windings).  
Call one of the ends that has only one wire on it ground, and the other 
goes to the beverage,  The other end of the grounded winding is 50 Ohms.  
This makes a 9:1 transformmer (from the ARRL books).

To make sure it works, use a 450 Ohm (or something close) ) resistor and
check the SWR with an SWR analyzer or low power radio.  Most of the ones 
I have made work up to 10 MHz without any problem.  This make great little 
gifts when visiting a DX station for a contest.

I will try a schematic using ASCII:

        o  To Bevridge (450 - 600 Ohms)
        |
        |    ---     ------------------o  50 - 75 Ohm 
        |   |   |   |   |
        (   |   (   |   (
        (   |   (   |   (
        (   |   (   |   (
        (   |   (   |   (
        (   |   (   |   (
        (   |   (   |   (
        |___|   |___|   |
                        V   Ground

I should give credit to N6AA who showed me all this.

Tree N6TR

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