VLF DX tests with earth-electrode antennas

Stefan DK7FC is transmitting 75W into an earth-electrode "antenna" and seeing if he leaves a trace on the RX at Todmorden in the UK.

"Hi VLF,

I'm sitting in my car while writing this email. I'm in JN39WI96GX and i transmit on 8270.000 Hz with a GPS locked signal generator into an about 450 m long earth antenna using two guide rails as the earth electrodes on both ends. On each end there are 16 (18) massive T-T poles holding the guide rail, providing a super good earth coupling. I measured that they are connected to each other.
The transmitter is on the air since 9:08 UTC running 550 mA with just 75 W DC inout power into my hand warm lossy linear mode VLF PA!

I'm amazed about the low losses! At DC i got 447 mA at 50.9 V. The wire is 0.4 mm diameter so it has 63 Ohm. That means the ground loss is just 50 Ohm !!!! Amazing! And i have no efforts to build up a ground connection here, i just need to connect the wire. Since the wire losses are higher than the ground losses, i can get maybe 2 dB more signal when buying some better wire. I already found a source that offers 0.75 mm^2 100 m loudspeaker cable (i.e. 200m wire)for just 13 EUR....

BTW i even have an ugly old scope here which is battery powered. I can see that the phase of voltage and current is slightly inductive, maybe 30 deg or so. So i could series resonate the antenna with some C. This is for the next experiment...

The signal becomes visible on my grabber now, in 424 uHz and also some bright pixels in the 3.8 mHz window.

I'm going to stop the carrier at 10:08 UTC, after 1 hour. Then i'll continue on 5.17 kHz!
BTW the antenna , if it works like a real loop, is beaming directly to Paul Nicholson ;-)

73, Stefan"