Trapped EFHW info

Started by caulktel, June 11, 2017, 06:58:42 pm

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Hi Joel,

I used 24AWG insulated wire and the higher dielectric constant of the insulation slows things down just a bit so yes about 63' for 7MHz and 14MHz will resonate at that length too.

You'll need a "coupler" (49:1 or 64:1 transformer) but not a tuner.  Trim for resonance at 14MHz and 7MHz will be fine.  14MHz is fussier about length because the waves are 2x shorter.  I like the wide-band transformer type couplers like LNR precision's since there's no variable cap to have to adjust.


Hi Bob,

I agree with you about the LNR transformers, I have several, and have built at least five myself, they are 60:1. They are what I use most of the time. I will try the 63' wire you mentioned and see if I can get it resonate on both bands. Thanks for your help.