4 ms·

I’d love to know HOW such a measurement is made. What’s the reference “ground”?

• zamadatix 7y ago
  Measure between 2 points of ground in a planned fashion, the difference should be 0 https://openei.org/wiki/Telluric_Survey https://openei.org/wiki/Telluric_Survey
  • matt_the_bass 7y ago
    cool thanks! Does this imply that the points a pretty far away from each other to measure an effect from such a large imf? If so, I’m curious as to the equipment that would enable such a measurement. This is A wholly different ball game than measuring ground currents across a pcb.
    • hwillis 7y ago
      In this case the probes were 40 meters apart. At that distance the voltage is normally ~40 mV, which is trivially measurable. Fluke makes a line of fancy multimeters for this kind of thing
      • matt_the_bass 7y ago
        Oh! Only 40 meters. I had assumed the distance must have been mush greater for these scale effects.