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Old August 3rd 09, 04:44 PM posted to rec.radio.amateur.antenna
JB[_3_] JB[_3_] is offline
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First recorded activity by RadioBanter: Apr 2008
Posts: 543
Default Counterpoise for an end-fed wire antenna

"KJ4NTS" wrote in message
...
I'm confused about the requirements for a counterpoise for an end-fed wire

antenna. I understand
that it's needed, but I don't understand what the requirements are.

Can a ground stake at the base of the feed point serve as a counterpoise,

or does it need to be
another wire running under the ground below the antenna?

If a wire is required, how long does the counterpoise have to be?

Would it be better to use insulated or uninsulated wire for a buried

counterpoise?

All these questions depend on your particular situation. In a typical
antenna installation you would first seek to follow the instructions for
that antenna. Especially if you don't understand the physics involved. You
will probably already have some sort of ground through the power supply.
Any better ground than that must actually be better to whatever energy you
are trying to "ground".

Someone mentioned RF in the shack and being bit from the chassis or
connector shell. The best way to avoid that is for the energy at the coax
connector to see 50 ohms, and for the radiating portion of the antenna to be
well out of the shack. In that case, you don't need an RF ground on the
radio.

A ground stake at the feed point along with a remote tuner should be
sufficient if you have really low resistance soil. You will probably
benefit by adding a counterpoise and you will probably never have a perfect
ground. It is better to have uninsulated wire because it will conduct into
the ground. Some think insulated is better because it will last longer for
a little expense in performance.

A remote tuner (or matched antenna) at the feed point, will keep the RF to
the transmission line and prevent high voltages on the line and keep losses
to the minimum.