I here describe a wideband HF RF choke design in pictues. The choke covers most of HF from 160m to 10m and will give a resistive part of the impedance R ( R+jX) that should be high enough to not cause overheating of the ferrites. It will also give a significant reacive load, but the resistive load cannot be cancelled by capacitive effects easily. The 9 + 1 core design above will give the resistance shown on the blue trace in the image to the right above. The other traces (red, green, pink) shows 5, 4, 3 turn designs that was first tried. Note that the fewer # of cores in the choke, the higher up in frequency the resistance peak occurs. Note the single external series core with two turns. That single core takes care of extending the resistance up in frequency above the lower peak (the peak that goes out of the graticule to the upper left). The material is the Fair-Rite 2643167851 material.
Wideband HF RF choke design version 1
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