Hello I'm fairly new to metal detecting and I'm having trouble with my fisher f5. I have done some experiments with a buried silver quarter and could not get a signal on it when it was 6 inches deep. I don't quite understand how the ground balance works and I'm thinking that might be the problem but I'm not quite sure. I know the f5 is a really good detector and I live in iowa so the ground isn't highly mineralized. Please help!