I recently posted a question on MDing near and around playground equipment and fences. Your recommendation was to get a smaller coil. I got my Joey 5x10 coil yesterday and tried it out today. Had wonderful success in an area I have done numerous times before, BUT when I get close, (within 18-20) inches to the iron fence, I still get a constant tone from my Explorer II. Is there a setting I should be following. I'm still learning the machine, so I usually flip back and forth from Quick Start Smart to Quick Start Digital. Sen about half way, threshold just audible. I have tried Sen all the way up and all the way down and still no difference. Help!!