[Elecraft] KAT2 with EFHW antenna

[Ron D'Eau Claire]

Stan, that's not a true half wave radiator on most bands. They suggest a
wire length of 20 or 30 feet, which will be efficient on 12 through 6 meters
where it's at least 1/2 wavelength long, but on the lower frequency bands
it's just a short random length wire with an auto-transformer to assist with
impedance matching. 

There's a huge difference between a full-size radiator and a short one that
is made "resonant" using supplemental inductance. It will work as you, I, or
anyone who has used a short, random length wire can attest, but it's
efficiency is much lower than a radiator that is physically a half
wavelength long. 

There's just nothing that can replace physical size for an efficient
antenna. Not too much is lost on even multiples of a half wavelength. The
impedance at a full wavelength, two wavelengths, etc., drops with each
multiple, but still remains far above that impedance of even a 1/4 wave
length radiator. And when dealing with any end-fed antenna worked against
ground, higher impedance at the end of the antenna means higher efficiency
for a given ground. 

73,

Ron AC7AC


-----Original Message-----

And for those with more money than brains (that would be me) you can 
purchase an end fed halfwave antenna from the Emergency Radio Club of 
Hawaii for $42.  I bought one and it works great with the entire 
Elecraft family. Great to have a simple yet efficient portable antenna 
that fits into a sandwich baggie.   This site also has the plans to 
build this one on your own if you would prefer.

The main website is at:  http://www.earchi.org/proj_homebrew.html

The page for building it yourself is at: 
http://www.earchi.org/pdf/endfed.pdf

And the page for the 'easy way out' is at: 
http://www.earchi.org/pdf/endfed20.pdf


73, Stan WB2LQF
KX1 #2411    K1#2994    K2# 6980    K3#5244     K9 #1 (Cocoa the 
Chihuahua)
Everything is QRP, even the dog.