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How Volts, Amps and Ohms Affect Locating

Amps = Current (signal)

Volts = Push behind Current

Ohms = Impedence or Resistance

Power (watts) = Volts x Amps

  1. Voltage is like pressure, it pushes the current down the line.  The greater the current flowing, the greater the magnetic field.
  2. The more amps applied to the utility, the greater the signal.
  3. If the resistance is high (e.g. dry ground), the voltage will be higher to push the current down the line.
  4. You are trying to overcome the Ohms.  Ohms are the resistance (in the case of AC, it is call "Impedance").  Ohms are trying to resist the current from flowing.
  5. How does the Frequency work?  Instead of the voltage guy pushing in a steady fashion, he pushes in a pulsing "push-push-push" pattern (Frequency).  The faster the "push-push-push" pattern, the easier the Amps can overcome the Resistance, so Frequency helps overcome Impedance. 
  6. For lines with greater Resistance (Impedance), raise the Frequency to help Amps to move further down the utility.
  7. In general, keep the Frequency as low as possible, because the higher it is, the easier it jumps to other utilities since higher frequencies help amps push across the resistance of the soil between the utilities.

For more information, visit the Radiodetection Technical Support page at: