I won't keep jumping in here wasting all you nice folks time unless I have a real important question. I used my F4 today again with the DD coil and was amazed with the accuracy of the id. So I am thinking that my round coil has a problem. Between my wife using it (she loves to detect as much as I do) and myself in the last 2 days we have found 6 rings,20 or so quarters,a bunch of nickels,dimes & pennies. I can honestly say that the F4 is even better than I expected it could be. It sure has brought the fun back into detecting. I thank all of you for your comments,opinions and answers. Steve (upstate New York).