The single disk small machine has a black backing and the dual disk small machine and the 3kW machine both have a black rear disk. Could there be a reason for this black material? Borrowing an idea from Implosion from Holland on the testatika Yahoo! Group I cut up a vinyl record for the back disc with the hope that it would hold a charge, replacing the need for any high voltage power supply. This would therefore give me good oscillations measured across the antenna keys. It worked like a charm! The front disc was the disc with sectors on both sides where each inner sector was made up of two strips of metal and where sectors on both sides were electrically connected and all sectors were electrically connected near the disc axis and where the outer sectors were completely insulated but the inner sectors were not.
See also my excellent results with vinyl material with my single disk small machine. Why the black material? It's known that the disks are first turned by hand and that after a few turns, the disks then turn by themselves. The "something" that taps into an energy source to get excess energy may need the oscillations you see above in order to do the tapping. Once the energy source has been tapped into, that energy may be used to:
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