Could T1 tune a counterpoise ?

[F5LCIjmb]

I have a coax-fed multiband dipole (for 40m and up) swung over a 80 ft  
Platanus acerifolia (what a luck !).
For 80m and top band, I use a switch (found in "Hints an kinks" many years  
ago) to make it a "LW".
My shack is upstairs, and I don't want to use the poor AC ground for many  
reasons.
So I need a counterpoise (maybe I'm wrong). It will be short and T shaped  
to minimize radiation, as shown in Moxon's book (that's my bible).
In a previous location I had successfully tuned an upstairs ground lead  
for top band : it was very pleasant to see the antenna current increase  
(with a home made RF-peg) as I tuned out the gnd wire reactance.
For now I have not enough spare time to DIY (although I assembled the K2,  
hi).  Had a think about Ten-Tec artificial ground, but it's difficult to  
find here, and now I fully appreciate the auto gearbox of the K2.
Then T1 appears : if it searchs for a current maximum, that should work,  
why not ?
So, is it possible to use it as a counterpoise-only tuner ? (KAT2 does the  
rest)
Regards to all es 72 de F5LCI in the french countryside,



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[Ron D'Eau Claire-2]

I need a counterpoise (maybe I'm wrong). It will be short and T shaped to
minimize radiation, as shown in Moxon's book (that's my bible). In a
previous location I had successfully tuned an upstairs ground lead for top
band : it was very pleasant to see the antenna current increase (with a home
made RF-peg) as I tuned out the gnd wire reactance. For now I have not
enough spare time to DIY (although I assembled the K2,hi).  Had a think
about Ten-Tec artificial ground, but it's difficult to  find here, and now I
fully appreciate the auto gearbox of the K2. Then T1 appears : if it searchs
for a current maximum, that should work, why not ?

So, is it possible to use it as a counterpoise-only tuner ? (KAT2 does the
rest) Regards to all es 72 de F5LCI in the french countryside,


Excellent idea, IF the T1 actually tuned for maximum current. Unfortunately,
it does not. It uses a bridge circuit to provide a 50-ohm non-reactive load
to the transmitter. While that might be better than a short, untuned
counterpoise, it is far from ideal.

What I have done in your situation is to use a simple coil. A short
counterpoise will be capacitive, so what you need is an inductance to bring
it to resonance. If you are using a barefoot K2, a small inductor tapped
every turn should be FB. I once made one wound on a cardboard tube that once
held a roll of paper towels. What Ten Tec does is add a variable cap in
series with the coil to allow for small adjustments in between the taps, and
to provide a way to tune out inductive reactance in a counterpoise when it
is electrically longer than 1/4 wave.

You need a current indicator. That's easy. A small flashlight bulb in series
with the counterpoise. Short it out after finding the tap with the greatest
current.

Your QTH makes me hungry for some French Bread and a wedge of Brie.

Ron AC7AC


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