Ok this lake bottom at a small beach club in my town has been closed for years, it was used in the 30's to about the 70's and I have worked it for years with my 1265X and puled out lots and lots of silver and jewelry and gold rings and just stopped going there cause stuff was real thin ( the water was still in the lake), about 3 years ago I got my F75 LTD and they drained the lake every year, well the F75 did ok there, she was real noisy could not use the 11" coil unless SEN. was about 40, but she still found some deep stuff (silver dimes & some gold rings) and then the last time i was their I found 1 stinken Lincoln, so I kind of wrote that lake off, Well got my headphones back so I figured I'd test them out with my 1270 with the 8" coil: Primary IRON DISC 10, Sen Max ( with Threshold Noise ) Vol. 10 Secondary Normal Disc 3. Well only found 7 coins at this hunted out lake but I could believe it, and all were at least 8"s down. This lake bottom must some real heavy minerals for the F75, sure am loosing faith with the F75, where I found these coin I've been over that spot 10 or 20 time almost like a grid, and they came right through the iron trash on a couple of coins. My money still on the Beep and dig machines. Going back with my 10.5 and the "GRID Engineer Tape" Ron............ 3 Mrec's and 4 Wheaties............