[Elecraft] EFHW

[Ron D'Eau Claire]

If you are planning to use the autotuner in your KX3 or KX3, I'd strongly recommend the random wire. I work on the basis that there is no "passive" device. Anything between your finals and the 'aether' is either a gain device (external amp) or a loss device (transformer or "balun", transmission line, etc.) The fewer loss devices the better, no matter how efficient you try to make them. 

As others pointed out, to get any real benefit from the EFHW it needs to be a real half wave or very close to it, necessitating a transformer to shift the impedance into range of the ATU or a purpose-built matching network (tuner). Shifting the length from a half wave simply turns the wire into a "random wire".

One other difference between an EFHW and random wire is that it is much easier to spend a lot of money on a commercial EFHW too, Hi

73, Ron AC7AC 

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dan Presley
Sent: Wednesday, February 8, 2017 2:42 PM
To: K2
Subject: [Elecraft] EFHW

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


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