Can Use the Earth as an Antenna? The Earth Electrode Antenna

Can Use the Earth as an Antenna? The Earth Electrode Antenna

Can you really use the  Earth as a radio antenna? That is exactly what some of our Radio Amateur friends are trying to do! Today I noticed a Twitter post from N4AKV which roused my curiosity on the Earth Electrode Antenna. He had used two copper wires driven into the ground about 70 feet apart and connected with a wire in the middle. This was driven off centre from coax. He used 20 Watts of power on FT8 for a few minutes and showed a wonderful propagation map which ran to many neighbouring states in the United States of America! This prompted me to read about this Earth Electrode Antenna. Some have even mentioned that “One man’s ground is another man’s antenna”!

SP5XSB had documented his work on 475.765 kHz using Earth Electrode Antenna on Facebook in 2014. He was using 25 Watts power output into electrodes 20 meters apart. Antenna was connected to 50 Ohms TX filter with serial 2.2 nF capacitor and noted SWR between 1.1 to 1.4 according to weather. Capacitor value was chosen for lowest SWR. Running WSPR, best DX contact was OH8HTG at 1392 km! Connection was using an isolated wire and there was no difference between the wire on the ground or on a fence. He thinks that his garden soil is composed of sandy clay.

In another report by G3XBM, again in 2014, the test was on 472 kHz WSPR. One end of his Earth Electrode Antenna was tied to the mains earth. The other end was a 1 m earth rod driven into the soil. Interconnection was with a PVC covered wire along the fence at a height of about 2 m. The spacing between the mains ground in the shack and the far electrode was about 12 m. He reported modest results of being copied by G0LRD at 25 km and G3ZJO at 79 km.

Earlier he had documented a few conclusions about the antenna on blogspot, which are interesting. He thought that the Earth Electrode Antenna behaves like an H-field loop transmitting antenna, with strongest signals in the line of the loop and weakest at right angles to that. It was also good as RX antenna and had about 50-60 Ohms resistive load providing good match to his transverter. OR7T calculated the effective loop area to be 290 sq m with radiation resistance of 0.017 Ohms and that was indeed a big loop! Compared to a 9 m high top loaded Marconi antenna, performance was only 8 dB down. Performance may vary depending on the geology of the location.