Building a 9:1 UNUN with FT-140-43 Toroid

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This is post 2438 in a continuing series of simple ham radio antennas.

Thanks to Gil of the "" youtube channel for this useful and often necessary accessory for random wire multi-band end-fed wire antennas.

The step-by-step assembly process is clear and easy to understand.  This would make an excellent weekend project.

Here are some general comments from Gil:

Building a 9:1 UNUN for a random-wire multi-band end-fed antenna using an FT-140-43 toroid instead of the usual T106-2. Presumably the ferrite toroid works better for the lower bands, 40 and 80m, and as well for the upper bands, I would guess up to 10m, not sure about 6m. It remains to be tested in an upcoming video. I should have measured SWR with a 470-Ohm resistor between ground and antenna wire but I forgot. A random wire by the way is any wire which is not a half-wave of any band to be used. The 9:1 UNUN usually requires a tuner. End-fed antennas: EARCHI UNUN: The field test link will be here as soon as completed.


Thanks for joining us today.

Aloha es 73 de Russ (KH6JRM).



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