LF: Earth loop

["Tony Baldwin" <ei8jk@o2.ie>]

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.