[Elecraft] KAT3 Specs

[Ron D'Eau Claire]

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

I was looking for the specs for the KAT3 tuner option for the K3.  Just 
wondering what the tuning range is and if it will fully replace the LDG 
AT-200 I'm currently using.  After years of coax fed dipoles I finally 
got around to experimenting with open wire fed dipoles.  I'm quite 
impressed with the results. I'm currently using about 90' of wire fed 
dead-center with 450 ladder-line into a 1:1 current balun.  The LDG 
AT-200 seems to tune it just fine on everything from 40 to 10.  The next 
one will be 135'.  Hoping the KAT3 will handle it so I can have one less 
piece of equipment on the desk.

Doug -- K0DXV
Clark, CO

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I don't know the LDG so I can't answer your question about the matching
range but I can say that your 90 foot wire will work as well as a 130 foot
wire on 80 meters. Crunching a few numbers, the "loss" caused by the
shortening is less than 0.2 dB. Indeed, you'll find virtually no additional
penalty operating it on 160 meters at that length.

If the tuner won't handle some frequencies, adjust the length of your
antenna (or feed line if that is easier). You should be able to find a
length that the tuner can match on all the bands without significant
penalty, at least on 3.5 MHz or higher. 

The impedance gets quite low when the antenna gets down near 1/4 wavelength
or less and might exceed the KAT3's range. Assuming a height of 40 feet, the
impedance at the center of a 90 foot wire at 3.5 MHz is about 13-j600 ohms
while at 1.8 MHz it drops down to only about 0.6-j1800 ohms. The feeder will
tend to raise that impedance, assuming it isn't more than 1/4 wavelength
long. 

Ron AC7AC