Testinterface for baluns

Dear ham operators,

a few weeks before I bought an analyzer with tracking generator. Since this time I works very often with this equipment, learn all over dB and the mathematics around. Special the measure of baluns was very interested for me. Measure the attenuation in equal phase and the attenuation in the through direction was very interesting.  For this measure I need resistors in the input and output of the balun. The input resistor is 50 Ohm (two time 25 ohm) and the output resistor(s) are different from the transmission ratio 1:1 ...... 1:12. In my working box I found a switch with two-level an 4 switches, so I can build an interface with the most popular transmission ratio of baluns 1:1, 1:4, 1:6 and 1:9.

I built it in a plastic box because I don't need a common earth. The analyzer is connected intern with earth on the tracking generator and analyzer so I needed only the middle of the cable for measuring the balun. The trick is to divide the input resistor and the output resistors in two resistors (2*25 Ohm) and in the middle the generator will connected. Also the output has the same connection from the middle of the output resistors to the analyzer. Now you can measure the process of the attenuation in fact of frequencies where the balun goes in saturation and also the equal phase attunuation of the balun.

The hole interface is shown next and also the circuit diagram.

Hole interface                                                                                        Front with switch

Intern connection                                                                                    Plan            ---> Bigger view

Arthur     DL7AHW

Visitors since 06.07.2010