Recent content by mcstatz5829

  1. M

    Water Freezing in Space

    There's no thermodynamics forum, so I'll post this here. Things "freezing" in space has always bothered me ever since Tim Robbins removed his helmet while in orbit around Mars...
  2. M

    PPM Ammonia/pH

    Do you know if water conditioner can throw off the tests? I'm in Indiana with very hard water and my city uses chloramine. First go at this, I filled up from the tap and used a water conditioner designed to remove the chloramine/chlorine. I then used the tank to urinate in for a week...
  3. M

    PPM Ammonia/pH

    Thanks! That's exactly what I needed to know. I did some googling over lunch and was able to convert to molarity (assuming pure ammonia solution) and came up with something similar. Been over 10 years since I've been in a chemistry course. Interesting if the test kits only include NH3 and...
  4. M

    PPM Ammonia/pH

    Hi everyone, hoping for some quick help. I’m trying to get the chemistry right for an aquaponics garden I’m building. I screwed up pretty bad the first time and just swapped out almost 100% of the water (there was a residual 2-3 gallons in the bottom of the growbed). Last night added in about...
  5. M

    Earth: Resistor or Capacitor?

    I don't understand this. You are talking about conductor to ground resistance? If so, the ohms/meter unit doesn't make much sense - it implies a 2 foot grounding stake would have double the resistance of a 1 foot grounding stakes, which doesn't make sense to me.
  6. M

    Earth: Resistor or Capacitor?

    So then at the frequencies we deal with, it acts primarily as a resistor. And from the SWER reference above, one with very low resistivity. The practical question we have at hand is whether to train our technicians about ground path return, and if so, how. And that started the discussion if...
  7. M

    Earth: Resistor or Capacitor?

    To clarify from some posts above - most of the time the facility we are locating is insulated from the earth. And yes, it is indeed the magnetic field that we are detecting.
  8. M

    Earth: Resistor or Capacitor?

    Resonant frequency - possibly, I would have to ask the equipment manufacturers if they use that for some of the detection. We don't modify the frequency. The receiver has multiple antennas for detecting the magnetic field. Simple version: The user moves it until it's registered a peak...
  9. M

    Earth: Resistor or Capacitor?

    So question I think is whether A) or B) is more correct. I think as F increases, Rearth decreases, and Cearth increases - the models converge. My interpretation is model B - there is no return through the ground. The earth is simply absorbing and supplying charge like a capacitor. But these...
  10. M

    Earth: Resistor or Capacitor?

    I work for a company that locates underground cables and pipes. We apply an AC signal to the underground facility and to be able to detect the location. Take the simplified drawing above. Two transformers grounded with a buried electrical cable. We use a transmitter and connect it to one...
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