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LF: Earth loop

To: <[email protected]>
Subject: LF: Earth loop
From: "Tony Baldwin" <[email protected]>
Date: Sun, 20 Jun 2010 14:04:56 +0100
Reply-to: [email protected]
Sender: [email protected]
I have also been experimenting with this sort of antenna on receive.
Mine is wire about 80m long and follows the hedge boundary draped over bushes about a metre above ground level and terminated with an earth rod. Most of the way it follows underneath an overhead power 240v line that goes from a transformer to my neighbours property. I did this on purpose just to see what would happen and to see if it coupled itself onto the mains wiring about 9m above.
I was monitoring the 500 KHz WSPR activity on Friday evening on my full size G5RV with the feeder strapped and was getting ...
2010-06-18 21:42  G4JNT  0.503882  -22  0  IO90iv 0.2
2010-06-18 21:36  G4JNT  0.503882  -22  0  IO90iv  0.2
I changed over to the earth loop/short beverage plus the main station earth and immediately the QRM went way down and up pops PA0A along with G4JNT at the same strength.
2010-06-18 22:06  G4JNT  0.503882  -22  0  IO90iv  0.2  
2010-06-18 22:04 
 PA0A  0.503907  -17  0  JO33de  5  
So it seems that something is working well here although I'm not sure what.
Later today or tomorrow when I get time, I will lay out another wire at 90 degrees to the other one and also 90 degrees away from the overhead lines. It will be interesting to switch between the 3 antennas after sunset and see what happens.
The existing wire is roughly ne/sw and the new one will be almost exactly north/south.
The reduction of the QRM was very noticeable and somewhere in the order of 6 'S' points, but only on skywave QRM as I also tested the system out during the day on a Spanish MW station on 551 KHz and both antennas seem to be very similar in both signal strength and noise.
Fun isn't it.
73 de Tony, EI8JK, IO51dn.
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