Dual self resonance?

[Ism]

Can someone explain the following? I have 2 self resonances of my coil. The higher frequency is resonating at an increased P-P voltage. I figure one is a harmonic but which one? Wouldn't the harmonic would be a lower P-P voltage? Everything I've read leads me to believe the actual self resonance should be the lower of the two frequency's. Sorry the scope pics are dim but its to illustrate the 2 frequencies and the P-P voltage difference. I'm using the "Fast Coil" self resonance setup.

[WM6]

Can someone explain the following? I have 2 self resonances of my coil. The higher frequency is resonating at an increased P-P voltage. I figure one is a harmonic but which one? Wouldn't the harmonic would be a lower P-P voltage? Everything I've read leads me to believe the actual self resonance should be the lower of the two frequency's. Sorry the scope pics are dim but its to illustrate the 2 frequencies and the P-P voltage difference. I'm using the "Fast Coil" self resonance setup.

Piece of cake if you use spectrum analyzer.

Here can you find it for free (I checked it- is working fine):

http://www.geotech1.com/forums/showp...1&postcount=35

Otherwise, answer on this your question: Wouldn't the harmonic would be a lower P-P voltage? is: Yes!

[Ism]

Thanks WM6, I downloaded the software. Will build the probe soon.