Even the lowest setting will probably penetrate the ground some, depending on the target. If you're looking for something in particular, you might want to try an air test on something similar and notice the distance until you lose the signal, shorten your shaft and detect a little less than that distance above the ground.
Now I have a question.....why would you want to :biggrin:?
I do a lot of surface hunting now that the ground is frozen so deep...I don't change anything on either machine - just use the default settings. That way if something really interesting shows up - I can mark the area (physically) and in a notebook I always carry - so I can come back later when the ground thaws...
My snowblower axle broke today While looking through the manual I noticed a "special washer" that was no longer there. I figure special means more $$ so did a quick look with the MD and found nada. I think it wore out years ago and dropped off as there appears to be wear to indicate just that. It's 33 years old. Thanks.