21 Jan 2013

Back on the earth-electrode antenna on 472kHz

The red dots show where the wire to my far earth rod goes - under the snow!
This afternoon I've installed a coax cable from my operating shack down to the back of the garage where I do my radio building and where I can connect to the earth-electrode antenna running down the back garden. Now I have my 472kHz transverter in the garage too so it can connect directly into the earth-electrode antenna without any matching. Even with 8cm of snow on the ground and nothing of the antenna visible above the snow line (!) this antenna is still radiating a decent signal with reports already this afternoon from G3ZJO (-22dB S/N) and G3XDV (-12dB S/N) at good range. I find it truly amazing this system works at all.

I am signing G3XBM/1 on the WSPR database to distinguish my signal from that transmitted using a Marconi where I use G3XBM.  I hope no-one minds me using this suffix for a short period, but it is very much in the interests of good research. The signal level with G3XDV at 61km is about 8dB weaker on the earth-electrode antenna than on the vertical Marconi.


Graham said...

The more I read about your success with this very simple but effect antenna the more I am tempted to try the same.

Your yard with 8 cm of snow looks much like my own except that we got about 10cm or over this past weekend and that is on top of the 20 to 30 that was already there ;)

I don't know how deep the ground is frozen this year as we really haven't had that much very cold weather yet. I might try driving in a ground round to see and if successful I may just have copy of your earth electrode antenna functional before too long.

cheers, Graham ve3gtc

David said...

Hello Roger,

I've not managed to see your signal so far this evening. I did spot you a few times yesterday when you were running with the Marconi.

Rx here is an Icom 703 with a homebrew 30db gain tuned preamp. Antenna is a totally untuned ZS6BKW wire antenna straight into the preamp.
-29 db seems to be about the weakest signals I can decode with this setup.

David G7UVW

Roger G3XBM said...

Thanks for trying David. The earth-electrode antenna is about 8dB down on the Marconi in the best direction and considerably worse than that in the directions orthogonal to the alignment of the electrodes (loop in the ground?).