I'll start a thread on this machine.I have 2 of them one setup with the 3X7 coil for heavy trash and one setup with either the 11&quotcheesysmile: or the 6X10 concentric coil.This detector is my all time favorite for coin hunting.It's light,it's super fast processor and small coil will amaze you coin hunting in heavy trash.It seems to be hot on silver.Here in North Carolina there is real low mineralization where I hunt it goes real deep on coins.In Montana in the mineralized gumbo soil it would chatter in the real dry soil conditions.It is effected by EMI but I have turned the sens down to 29 and was still able to find coins to 7 inches.I run mine at sensitivty of 90,discrimination 6,notch 0,tones 4 high and DE process.My F 75's ground balance at the factory preset as the soil is so low in mineralization it doesn't have to compensate(in North Carolina).Bill