If you’ve been eyeing an end-fed half-wave for park activations, here’s a build log I really enjoyed. Jeff put together his own 49:1 unun using two T140-43 toroids, #20 magnet wire wound 21:3, a 100 pF high-voltage capacitor and a Type-N connector, all tucked inside a restaurant takeout container. His total came to about $17 and 161 grams.
What I like most is that he tested it properly. He swept it on a NanoVNA into a homemade 3.2k dummy load before ever going outside, then ran it as a sloper on a POTA/WWFF outing, working Europe on FT4 at 20 watts and filling the log on 20 m SSB. He’s upfront that it’s a build log rather than a full step-by-step, and he points to other references for winding details.
Visit them: End-Fed Half-Wave & 49:1 Unun on Jeff’s blog
Leave a Reply