EFHW (was Small QRP antenna)

[Michael Babineau-2]

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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[Jim Brown-10]

On Fri,12/30/2016 6:02 AM, Michael Babineau wrote:
> Anyone interested in EFHW antennas should read Steve, AA5TB’s excellent website

Here's another great way to end feed a half wave that Steve didn't think
of. It originated with an idea that N6LF published.

http://k9yc.com/VerticalDipole.pdf

Using a connector and barrel for the center was W6GJB's idea. For
backpacking, a BNC to female Pomona adapter (Pomona is the official name
for double banana jacks and plugs) could be used instead. To make this a
multiband antenna, simply use a shorter or longer piece of wire for the
top end and move the choke to a matching position along the coax.

73, Jim K9YC

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