Measurements of the RF characteristics of earth lighting with the Galileo probe lighting experiment.

We present the results of some measurements of earth lighting made with the functional unit of the Galileo probe RF lighting experiment. The frequency range used is ~100 Hz - 100 kHz. The measurements were carried out in conjunction with simultaneous studies of lighting sources made by the University of Florida lighting research group. We find that the typical RF pulse duration times are 30 microseconds, independent of lighting source distance 250 km. We also find that the time between successive pulses is either quite short ( 64 microseconds), corresponding to the time between intracloud pulses and to the time between bipolar pulses, or occur around 100ms, corresponding to the time between return strokes in ground discharges.