LF: MF earth-electrode improvements

To:	[email protected], "[email protected]" <[email protected]>
Subject:	LF: MF earth-electrode improvements
From:	Roger Lapthorn <[email protected]>
Date:	Tue, 18 Feb 2014 20:16:06 +0000
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Since starting 474.2kHz WSPR TX with the 15m baseline earth-electrode "antenna" I have made 2 improvements:

(1) Resonating the "loop" with 50-200uH of inductance, empirically to give most antenna current;

(2) Adding a 4t:14t 3C90 based step-up matching transformer between the transverter and coil. Again empirically chosen to give best antenna current. This means the earth-electrodes look like several hundred ohms at this (new) QTH - quite a surprise.

My signal with G3WCB (101km) is consistently 3dB stronger today and I already have had French and Dutch spots.

Any further 474.2kHz WSPR spots would be much appreciated.

No further changes are now planned until the layout of the longer baseline, which requires help with the earth rods because of my poor health and stamina currently (stroke). The transverter runs cold, suggesting close to class E operation.

73s

Roger G3XBM

http://www.g3xbm-qrp.blogspot.com/

http://www.g3xbm.co.uk
https://sites.google.com/site/sub9khz/
http://qss2.blogspot.com/
http://www.youtube.com/user/g3xbm

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