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