I agree with christ000 bigger coil, wet ground, also I have found 25 or more to 1, ratio of modern pennies to modern dimes or quarters plenty of times, the silver has to be there, but who knows what the ratios of pennies are until they start diggin'? Some sites have better ratios than others, at least you know your site is not hunted out! If you are walking east to west as you scan, after you finish, scan the whole site again walking north to south. Orientation of the coins in the ground can mask their presence from one direction and not from the other. Also I get more deep coins if I overlap my scan widths. If I was in an area like yours I would stand in the same spot for three scans then move ahead a little and then three scans again. I know that sounds boring but beats wondering if I left silver behind! HH