A small QRP EFHW transformer is possible using a BN43-2402 balun core from 7 - 29 MHz. As you can see in the plot the swr is verry flat from 40-10m so a capacitor at the input is not needed. A 3300 Ohm resister to the ground was usesed for the plot. With just 20.3m wire this makes a nice 40-10m antenna. You can also use the 34uH coil of the endfed down this blog to create a compact 3 band atenna of just 12m long. I think 20 Watts PEP is the max. power here. Be carefull, each pass is 1 turn here.
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