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QHB #8 -- April 2002


Build a Low Power 4:1 Balun , by Charles Greene, W1CG

Figure 1. Two types of coiled transmission line 4:1 baluns using ferrite or powered iron cores: (A) The Guanella or Current balun; a two core balun like the one described in the text is shown. (B) The Ruthroff or Voltage balun.

Picture 1. A single core of the two core current balun with the coils connected as a voltage balun.

Picture 2: Lead a cable tie around the core and one end of the wire pair about 3" from the end and tighten it.

Picture 3: Balun core in vise showing heat shrink tubing on outside of windings.

Picture 4: Balun core with six turns showing crossover on the seventh turn.

Picture 5: One completed core.

Picture 6: Completed two-core 4:1 balun.

Picture 7: 14 turn version of balun in watertight enclosure for installation at top of Off Center Fed antenna.

Figure 2: Block diagram of test setup.

Picture 8: Test setup showing some of the equipment used.

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Last Modified: October 13, 2002