[Elecraft] EFHW

[K9MA]

Two distinct advantages of the EFHW: It's high feedpoint impedance means 
a minimal counterpoise is required and very little power is wasted into 
the ground system. Second, the high current part of the wire, which does 
most of the radiating, is a quarter wave from the feedpoint, which can 
usually be much higher than the feedpoint.

The EFHW can be used on harmonics.

The down side is that the high impedance is beyond the range of most 
autotuners, so a transformer or external tuner is required.

I've been using a 40 meter EFHW for portable operations, mostly on 40 
and 20 meters.  I support it with a single 11.5 meter pole about 1/4 the 
way from the far end, like a lopsided inverted V. It seems to work quite 
well.  I have a homebrew QRP tuner, but I use a commercial one for 
higher power.  I've used the same antenna on 15 meters and, with a 
couple longer radials, on 80.  (It's a quarter wave on 80, so there's 
some "RF in the shack", but it hasn't been a problem as long as I keep 
my fingers of the metal parts when I'm transmitting.)

I'll gladly share the design of the QRP tuner.

73,

Scott  K9MA

On 2/8/2017 16:41, Dan Presley wrote:
> Wanted to get some thoughts from folks about pros and cons of an end fed half wave for portable/SOTA use, as opposed to just using a random length wire with a counterpoise connected directly to either the KX2 or 3.(I think Eric recommended somewhere around 28’ depending on the band coverage).Is there any particular gain advantage? To me the only obvious advantage is not having to deploy a counterpoise-with the end fed usually the length of coax will act for this, and of course the need for a suitable Un-Un,usually 9:1. My preferred antennas these days are lightweight resonant dipoles, which is fine assuming you have room to erect them, and second is a magnetic loop which I’ve had good luck with. I use the Alexloop-very light and easy to set up;ground and height independent generally. But-since you never quite know what will work best I try to be ready for whatever comes up. I have a variety of lightweight poles to use with wires.  I’ve had pretty good luck with throwing a random length in a tree or pole with a counterpoise, usually elevated if possible.The auto tuners in the elecraft rigs are excellent in my book. I think over the years I’ve used a bunch of portable antennas except the EFHW-just curious what the advantages might be.
>
> Dan Presley  N7CQR
> n7cqr at arrl.net
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to k9ma at sdellington.us


-- 
Scott  K9MA

k9ma at sdellington.us