DC single wire transmission
A very simple system, which is perhaps as unsurprising to some as it was surprising to me.
With the Negative connection from a 12V battery going into the ground and the Positive wire used as a single wire across the yard, 5x LED’s will light. The Negative side of the LED’s goes into the ground.
The output from this 13.2V battery at the LED’s is 13V at around 5mA. Not a lot, but very useful for running such small loads.
The wire length can be how ever long or short is required and the fiures don’t change, regardless of distance.
It also has a use for testing Ground conditions within Tesla tower experiments or radio. A dimmer bank of LED’s meaning a drier soil, brighter for more moisture.