Hi Don and thanks for the suggestions. Yes, I already have a 67 foot
doublet fed with window line as well as simple wires and counterpoises
in line with page 10 of the KXAT1 manual. They work just fine. No
argument there.
But I stumbled upon this "linear loaded" vertical antenna and thought I
might try it. It's is a 20 foot piece of 300 ohm TV line with the
conductors twisted and soldered together at the top and taped to a
twenty foot crappie pole. At the bottom, for working 20 and 30 meters,
both of the conductors are connected to the red BNC terminal on the KX1
making the the radiator just a "fat" 20 foot wire. For working 40
meters the bottom conductors are separated and one goes to the red BNC
terminal and the other just hangs loose making it a 40 foot antenna.
The write-up I found states, "On 40m the folded wire creates a linear
loading effect due to the capacitive coupling between the two wires
(note that currents are not equal and opposite so there is no
cancellation of signal as you might initially think). This added
capacitance allows the wire to be resonated on 40m by the internal tuner
in the K1, KX1 or also by the Elecraft T1." The fellow who offered this
antenna idea said that he had been using it successfully for quite
awhile.
Adding the BL2 is my idea because it will be part of the solution for
making the bottom connections. My intent is to come up with a "decent"
portable antenna that I can erect anywhere in just one minute. I want
to come up with some creative way to make all the pieces work together
effortlessly, rapidly and reliably, including dealing with the crappie
pole. My dream is to drop the crappie pole into a homemade holder on
my camp chair, push up the pole with the antenna following, walk the
roll of ribbon cable out in a straight line, go back to the chair, sit
down, turn on the KX1 and start operating! It's my springtime
project....
I ordered a 100 foot role of ribbon cable so I can do a little
experimenting with opening up the ends.
On Fri, Mar 10, 2017 at 09:44 PM, Don Wilhelm wrote:
Stan,
It can be made to work, but will be a real "bear" to adjust to
resonance unless you separate the ends.
If you are feeding with 300 ohm twinlead, why not make a 66 foot long
center fed dipole out of it.
Alternately if this is for portable work, us no feedline at all - just
a BNC to binding post adapter at the KX1. Use 2 lengths of wire as is
shown on page 10 of the KXAT1 manual.
73,
Don W3FPR
On 3/10/2017 7:14 PM, stan levandowski wrote:
I found the plans (June 2010 Elecraft Reflector) to build a 40/30/20
meter "linear loaded" portable antenna for my KX1 (using a crappie
rod,
300 ohm twinlead for the radiator, a BL2 balun, and ribbon cable
radials
cut to 1/4 wavelength for each of the bands (16, 25 and 33 feet).
My question is how terrible would it be to use a piece of that thin
computer ribbon cable cut to the three lengths but NOT separated?
This
would make it easier to deploy and roll back up.
Has anyone ever tried using unseparated ribbon cable counterpoises?
The
materials are on order and I'm sort of anxious to know.
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