How deep does the threshold and discrimination work on the mxt in all the different modes using 6 inch coil.Method i use for deep coins stomp ground to get better reading go through different modes turn sensitivity up.What iam curious about is iron reading at 9 or 10 inches is this actually a coin at that depth not giving a accurate reading.I have run across a few of these and was wondering on some technique everyone is using to grab deep coins.Thanks.I have been using mxt since they came out.