[Elecraft] Re: kx1 antennas

[jmeade at telebytebroadband.com]

"3 resonate wires mated on 3 banana plugs will eliminate the need for the
KXAT1"

I'll add my $0.02 here.  If you use a 1/4-wave radiator (33' on 40m) then
you need a 1/4-wave radial "system".  I say "system" because you should use
4 radial wires to make effective vertical antenna with elevated radials. You
might have to play with the actual lengths to get everything resonant, just
like you would have to do for a dipole. You can hook the ends of the wires
to the BNC-to-Banana adaptor to eliminate the feedline but you still want to
make a good vertical antenna "system" that works well.

Using a tuner eliminates the need for "pruning" the lengths to get the
antenna to resonate at the desired operating frequency. 

I think of a single 1/4-wave wire as a "counterpoise" which is not the same
thing as an effective radial system. The "counterpoise" is used with a
random wire antenna and is usually 1/4-wave long and brings the transmitter
end to ground potential. If you have a 1/4-wave wire antenna and a 1/4-wave
counterpoise wire, then you basically have a low dipole with half of it near
(or on) the ground.

I have learned that getting a match is not the only thing to worry about.
You also want an antenna that radiates the signal nicely. I put up a random
wire once at a park and the KX1 found a perfect match.  I called CQ many
times with no takers.  Later, I put up a 1/2-wave inverted vee supported by
an SD-20 pole fed with cheap 300-ohm twinlead and the Elecraft balun.  This
worked great and I had many QSOs that day on all 3 bands. On other days,
however, I have had great QSOs with just the random wire, with and without a
counterpoise.

There are many variables in how well a certain antenna works: band
conditions, power output, the radiation pattern - where the lobes from the
random wire fall, what trees are in the way, the height of the wire, etc. If
the band is in good enough shape, even the Miracle Whip can result in a QSO!

72,

John W2XS
KX1 #15