this post was submitted on 27 Dec 2024
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The main job of the unun is to match the impedance of the wire to the 50ohm feedline. You may or may not need a common mode choke to prevent RFI, but I had a lot of RF problems with my 40-10 EFHW. My radio was fine but my computer started to glitch out when was transmitting. That all disappeared once I looped my feedline through some ferrite.
Alright, good to know. Do you have any recommendations for which choke to buy? Or maybe I should make one? I know other people have snapped the small chokes on other problematic devices' wires that were causing issues. Was thinking of looking at those as they're cheapest.
Something like a FT240-43 toroid should work for 80m to 10m.
That is to make a common-mode choke on your feedline. You can always try to improve the RFI emissions from devices in your house by snapping on some ferrite on wall warts etc.