I am using the stock coil. Its always sounding off and the VDI's are jumping all over the place. There is a wide variation in the numbers. My ATP will lock onto a coin and not vary more than one number on either side of an ideal VDI for a particular coin. For instance a zincoln will hit 75-76 everytime,a clad dime 82-83. I dug a dime at 4" today that read 69-84 and all numbers in between. Its like the processor is looking for a number to lock onto. I've also noticed that in very dry soil that the VDI's will read higher for most coins. Anyone else experiencing these wide swings? I thought it was the coil at first and called Garrett, they sent another coil. It acts the same.