To find the kind of these devices, but really working and not commercial, you can go to visit this address.
http://jnaudin.free.fr/kapagen/index.htmAs it is grounded only, it cannot be said that it takes the energy from the air waves. Everything is detailed in the description.
All the excellent job this French Jean-Louis NAUDIN is doing is sometime very close with the Tesla inventions.
I went to see this man, and what he shows in his website is exactly what he really gets by his own experimentation.
