5 Sep 2013

First 8.976kHz VLF earth-mode tests from the new QTH

This evening, I did a couple of tests on 8.976kHz earth-mode from the new QTH with my 5W beacon TX. Initially I used the far earth rod about 12m from the house paired with a mains ground and set out on my travels with my loop to my usual first test site just outside the village. This is a car park for the Devil's Dyke walk. Unfortunately the car park has been invaded by gypsies, so I decided to move on to my next test site in the village of Reach (2km). Nothing at all was copied of my beacon.

Then I returned home and used the mysterious copper rod that goes into the ground just outside my shack as the local ground and still keeping the ground rod 12m away as the "far" electrode. I think this may have at one time been an oil pipe from a central heating oil tank. I have no idea where it goes. This earth-electrode pair has launched my 472kHz WSPR signal which has been copied in Belgium and Holland, but results have been disappointing, so I was not expecting much on 8.976kHz.

Rather than travel 2km, I parked outside my old QTH about 0.35km away in the village. My 8.976kHz signals were copied, but not very strongly. I suspect that this was true earth-mode without any real assistance from utilities as I do not believe either ground rod at the TX end is coupled to utilities grounds or copper pipes going into the road.
Weak signals over a 0.35km path

Path tested this evening plotted with Google Earth
Conclusions so far are that both for VLF earth-mode work and for 472 and 136kHz radiated work I need to much improve the earth-electrode arrangement in my garden to get credible results. I need to do some sort of mapping of the garden to see where would result in a good solid connection to copper water pipes going into the road (probably at the outside copper tap) and the best place to locate the "far" electrode as far away from the house (and other houses) and buried pipes as possible.

No comments: