LF: Earth electrode loop and 500kHz ERP

To:	[email protected]
Subject:	LF: Earth electrode loop and 500kHz ERP
From:	Roger Lapthorn <[email protected]>
Date:	Thu, 17 Jun 2010 21:41:26 +0100
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For a hand-drawn sketch "system diagram" showing the ground points, wire routing of the earth electrode loop antenna, please visit my blog at http://g3xbm-qrp.blogspot.com/

These notes are to clarify the diagram...

I'm using this earth electrode "antenna" to TX with on 500kHz and on sub-9kHz. It has not been tried on 136kHz (yet).
The wire runs down the garden fence (1.5m above ground) from the far electrode (1.5m in the soil) then coming up along the study roof to the upstairs bedroom where it connects to the inner of a coax cable. The outer of the coax is grounded to the copper pipes of the central heating system at this point.
The copper pipes within the house eventually join with the water pipes in the street (to the right in the diagram).
From the feed point, a 10m long coax goes through the house to the front bedroom where I have my 5W out transverter for 500kHz and my 4W sub-9kHz TX beacon.
No attempt at matching this has been made at all on 500kHz - I just connected to the wire and radiator at the end of the coax. On sub-9kHz I use a step-up transformer to match to around 40-60 ohms resistive (measured).
The local rock (below about 2m of limy soil) is chalky "clunch".
On 500kHz I've measured 34V with a diode probe at the feed point at the end of the coax in the rear bedroom (LHS of the house in the diagram) where it is grounded to the radiator and the wire starts its journey down the garden.

Questions:

Now, how big is the loop thus formed?
How much of this is within the ground?
What is the 500kHz ERP likely to be?

Best report this evening so far is -26dB S/N from G0KTN at 210kms.

73s
Roger G3XBM
--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM GQRP 1678 ISWL G11088

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