Ground communication is fun to explore. And there certainly is a lot of fascinating stuff to be observed via earth currents.I'd recommend the articles at www.vlf.it as a better place to start. Even though some of those also include vague references to New Age topics and most seem to jump to conclusions about what their observations "prove," at least they include more informative schematics than a plain-jane power supply and a rough layout of an earth antenna.
Maybe the elfrad site has been inactive for so long that its only surviving page has gotten defaced by French hackers. That might account for why its Moon link has nothing to do with presumed currents in that celestial body but is just a chart of full-moon dates and times, and why the Vulcania link is to a theme park advert. And I have no idea what a French interpretation of Chinese symbols has to do with the psychobabble about the universe being nothing but different "frequencies". Hence my foil hat suggestion. :)
Or why none of the other pages or informational links touted by the text seem to actually exist. It looks like a shell of something that may once have been more worthwhile.
(And don't even get me started on the absurd nonscience about earth attenuation being less over distance than EM in air, or the futility of "shielding" one end of a buried coax.)