What mysterious voltage?
When he built that antenna array, he had some problem with it, some kind of noize or other issue that he traced to electrical voltage that should not have been present ot had no obvious source.
IIRC (It’s been a while) he originally thought it was static electricity/wind derived but he tried isolating it and couldn’t. I can’t remember for sure if it was volts or amps but whichever it was, it had no scientific reason he could figure at the time for being present that he could determine.