KX1 Random Wire Antenna recommendations

[Chuck Gehring]

I have had some mixed results using Model 1296 BNC adapter using a 28'
Random wire with a 16' ground wire.  I would like to hear from some other
KX1 operators and what works for them.

73, KI4DGH

Chuck Gehring

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[David Toepfer]

I have quite good luck with a 33' ant and a 16' cp.  But I have a hard time
getting less than 2:1 on 20m.

kb3ipe

dt
.

--- Chuck Gehring <[hidden email]> wrote:

> I have had some mixed results using Model 1296 BNC adapter using a 28'
> Random wire with a 16' ground wire.  I would like to hear from some other
> KX1 operators and what works for them.
>
> 73, KI4DGH
>
> Chuck Gehring
>
> _______________________________________________
> Elecraft mailing list
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> You must be a subscriber to post to the list.
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[Bob Baxter]

----- Original Message -----
From: "Chuck Gehring" <[hidden email]>

> I have had some mixed results using Model 1296 BNC adapter using a 28'
> Random wire with a 16' ground wire.  I would like to hear from some other
> KX1 operators and what works for them.

See Bruce Grubbs N7CEE's write up on the KX1 in the ARS Journal at
<http://www.arsqrp.com/ars/pages/back_issues/2003_text/1103_text/N7CEE.html>
He recommends a 42' wire with a 16' cp.  Since I don't have a tuner in my
KX1 yet I tried it with my K1 and it tuned up nicely on all four bands.

Bob Baxter AA7EQ
Bisbee, Az.


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[Mychael Morohovich]

Hi!

In my experience, the counterpoise can be a tricky thing. Keep in mind that
minor changes in ground current can lead to substantial swings in antenna
impedance. That translates directly into changes in SWR. For instance, I use
an MFJ Artificial ground to tune a counterpoise for my 85' EFW. There are
some bands that I simply cannot match with a low SWR if I do not have my
counterpoise adjusted to see maximum current. On other bands the peak is
rather broad and it isn't as important.  Using end fed wire radiators can be
VERY effective, but they tend to take more effort for multi-band operation
if you care about keeping the ground current optimal for maximum efficiency.

It is not necessary to use an AG for series capacitance and inductance if
you are willing to either use a separate wire per band or adjust the length
of your counterpoise by either trimming it or folding it back onto itself.
The AG is, of course, more convenient and allows one to use the same 'poise
for more than one band- within reason (I use a separate 'poise for top band
and 80 meter ops).  To get the length right (the point at which the 'poise
sees maximum current) you will need some method of monitoring the current.
My MFJ AG has a built-in meter for this. You can also use a small light bulb
at the rig as an indicator and tune for max brightness. Of course, what you
are theoretically going for is a counterpoise of 1/4 wl, but it is not as
exact as this and some form of adjustment is helpful. QSYing within a band
can sometimes require a slight adjustment in ground current as well if the
antenna exhibits a high "Q".

For antics of the pedestrian mobile sort, I would probably use the
cut-and-try method to get the right counterpoise length per band if the SWR
was giving me trouble. One other thing worth noting is that I have found
with my KAT2 and KAT100 auto-tuners that small amounts of either capacitance
or inductance added in series between rig and antenna can work wonders in
helping the tuner find the right L/C combination on problematic bands. I
have a 335 pF air variable with banana jacks soldered onto frame and stator
that I use for this, as well as a goofy looking toroid wound on a T94-2 core
that is tapped at regular intervals with more banana jacks.

73,

Mychael AA3WF
K2 #1025


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[Leigh L. Klotz Jr WA5ZNU]

I am using a 28' top radiator and a set of 33', 24', and 16' radials,
one for each band.  With this set I can achieve a good match with the
KXAT12 in any situation.  (Good RF performance in any situation is
another question, still in progress..)

In use, I clip on one or more radials, and have left them at 1/4 wave so
I can use them elevated, but KQ6XA recommends and K6ACJ has confirmed
with an RF ammeter that shortening them about 10% for pedestrian
operation is optimal (see the table in the hfpack yahoo group files
section for exact recommendations).

Sometimes I swap things around and use 1/4 wave on the hot side and one
of the other wires on the ground, for example when I am too lazy to put
down 2 radials and just tie both to trees, making it an off-center fed
low dipole.

It ought to be the case that two radials 180 degrees apart would be a
lot better, but I haven't cut them yet, and I am not sure my waist pack
can carry 3 more wires.

>  I have had some mixed results using Model 1296 BNC adapter using a 28'
>  Random wire with a 16' ground wire.  I would like to hear from some
> other
>  KX1 operators and what works for them.
73,
WA5ZNU Leigh
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