Coils - a Comparison

Often copied is the metronix coil design.

And some coils are cheaper - in any sense. The following two plots illustrate the problems you are facing with some low budget coils:

  • strong frequency dependance
  • in this case even frequency AND magnetic field input dependance

 

 amplitude response

the metronix coil has a flat amplitude response and is independent from field strength

 

phase response

the metronix coil has a flat phase response and is independent from field strength