Hi all. About 8 or 9 years ago AMRAD installed what we called an
earth bipole. From our web page http://www.amrad.org/projects/lf/
"AMRAD has built a 1500 foot long bipole antenna. This is a wire that
goes through the woods and is connected on one end to a 300 foot
steel well casing and a ground rod in lake on the other. It is tuned
to resonance with two large coils near the ends and a ferrite toroid
transformer gets it all to 50 ohms for the transmitter. Initially it
was not strong back here in the Washington DC area. But now it looks
like the signal is pretty good further out. It may favor sky wave to
ground wave. Recent results have been good with reception into
London, Ontario Canada by Mitch Powell VE3OT. His zipped .wav file
can be downloaded <http://www.amrad.org/projects/lf/wa2.zip>here.
Note that it is almost 750k. This reception is about 324 miles or 521
km. Closer in we have reception confirmed from Steve Dove W3EEE/G3YDV
at Mt. Gretna PA. "
Note: here= http://www.amrad.org/projects/lf/wa2.zip
The wire was attached to trees about 15 feet off the ground and it
was fed about 100w and keyed at 5 wpm. We always had problems getting
people to listen for us outside the local area. We lost interest
after our FCC would not give us 137Khz as an amateur band.
One thing I learned during the installation of this antenna is that
if you step into waist deep mud and cannot get your self out, your
fellow amateurs will laugh and take photos of you before they will
help you get out.
I think that AMRADs and Stefan's experience show that this type of
antenna is worth some investigation.
Sandy
WB5MMB
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