[Elecraft] EFHW (was Small QRP antenna)
Michael Babineau
mbabineau at magma.ca
Fri Dec 30 09:02:58 EST 2016
Anyone interested in EFHW antennas should read Steve, AA5TB’s excellent website.
http://www.aa5tb.com/efha.html
Some of the currently available EFHW tuners (QRPGuys& QRPkits SOTA )
use the tapped inductor approach, but I much prefer Steve’s idea of using a transformer.
The advantage is that it helps to isolates the feedline.
I have found that this approach gives more predictable results when deploying the antenna
in different situations and with different coax lengths as compared to the tapped inductor
approach where the coax shield becomes the “counterpoise”.
I actually purchased a QRPkits SOTA Tuner kit, swapped out the toroid core for the one
Steve recommends (T-50-2) and wound a transformer as Steve suggests in figure 12
and it works great with the suggested elevated 0.05 wavelength counterpoise.
Cheers
Michael VE3WMB
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