J_P so we are on the same page. The spike you see on the computer for H is found using the earths field. The strong field that is turned on for a few seconds is only to cause the H protons to tilt. It's when this field is turned off and the H protons return to the earths field is the frequency read. So in the earths field H Protons @ 50nt should be around 2128 or so. This is what proton mags are calibrated to. look on page 9.
http://perso.infonie.be/j.g.delannoy...Technology.pdf
This is what I said. "Correct! But MFD uses the frequencies in the earth field that is in the audio range. That is all I am saying."