Thursday, June 10, 2021

Build Your Own 4:1 Balun

Build a 4:1 Balun... 

  Need 2 toroids, 2- 28 inches of solid wire, 
2 small zip ties, soldering kit, a 200 ohm resister. 

 Here is a project that does not cost an arm and a leg.. and you 

do it yourself or have a ham buddy come over do it together. 
 Put  together three 4:1 Baluns.  One was a 9 turn wrap and the
 other two were 12 turn wraps. Dave KD9HJJ wrapped the last
 one with the 12 turns.  They all checked good with the resistance  test.

The biggest concern to me was the dipole settings. It seems the more
 you read, the more confusing it gets. Graphs show the different
 locations for the balun. To me, the key was the 1/3 - 2/3 setting.
 But I did not take my own advice and used figures from one web 
site.. after too many trims, there was not enough wire.

Found a few youtube sites that had setting for length... found out the
 hard way again. Finally found one that set one up and showed the 
analyzer results. For the OCF Off Center Fed Dipole, he used 88.4
 feet on one side and 44.5 feet on the other. Some of this is factoring in
 the size of the wire used.. calculations for velocity factor.   That is 
what I used and all three, regardless of the number of windings.

Letting you know  that I used a L 15 toroid  on one and  the others were
 140-43.. not too expensive. 6 with shipping at $25.

 A lot of satisfaction building something that works and can be used ... 
can be seen on Field Day... 

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