I have just returned from a trip in outback Western Australia and have left behind a site where my AT Pro was constantly registering a strong signal and reading in the 35-60 mark. The signal is coming from a rocky outcrop and we did not have tools necessary to break it open. Being new to this (detecting) I am not sure if I am confident regarding the set up of the machine as I did not ground balance the unit. We did have a small 3gm nugget with us and I tried it on that and got the same response but quieter signal. We intend to return with digging tools but I am hoping the signal is not operator error. Any comments will be appreciated.