I have been using my sov gt since april in the auto mode. I would like to know how to effectively run the machine in the manual sensitivity mode, I have been using the auto mode and found some nice things but, my main interest is in finding old coins and getting the most out of the machine.I"m assuming that the first click to the clockwise position is maximum sensativity and that turning to far clockwise position is the least. Do you turn it out of auto and listen for falsing and /or threshold sound to be stable in using the machine in the manual sensitivity positions? Also I have one other question, when you change to a different size coil on the machine is it necessary to recalibrate the 180 meter? Thank you for your inputs and I greatly appreciate the advice