Is anyone using a field mill? I have always been going to make one. It consists of a horizontal metal plane with a conducting button on the surface which is insulated from the ground plane. A metallic maltese cross driven by a motor alternately covers and uncovers the electrode exposing/not exposing it to the sky. The electrode button has capacitance to ground which drops its impedance, but across that impedance is an AC voltage proportional to the ambient static field. A typical field in fine weather is 300 Volts/metre so the signal is not trivial. You should be able to make a field mill that works continuously except when actually shorted by rain. This is not a very high impedance device, and should show many marvellous things as the clouds float over you. You can calibrate it with a metal plate, say 12 inches above it with 50 volts on it. That should produce a uniform field on the mill. cheers, Neville Michie
> > I know you are talking about measuring lightning strikes but if you get the > impedance high enough, you can actually measure the earth's electric field. > (It is about 200V/m if I recall properly.) Interestingly it is affected by > the solar flux and solar wind. > > -- > Brian Lloyd > Lloyd Aviation > 706 Flightline Drive > Spring Branch, TX 78070 > [email protected] > +1.916.877.5067 > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
