Don't waste your time on Air Testing with the Infinium; Been there done that, accept that the machine does much better on in ground targets that have been there for a long time.
I have 1g bits that will air test at 6 inches and other 1g bits that donot sound off at all, there are far too many variables in play to try and get any indication of the machines sensitivity by doing Air Tests with nuggets.
Don't expect it to match the sensitivity of the ML GPXs on small nuggs, it just aint gunna happen.
If you work on the assumption that the Finny can find 1g bits and smaller under certain conditions and hit on 4 g bits all of the time with all of the coils then you should be able to relax while detecting.
One of the most important aspects of the Infinium is that you must scan slowly in order to hear the weak signals whether they be from surface targets or deep targets.
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