Thanks Danie, a good article indeed. I was not happy that my Surf Pi produced some false signals during and at the end of a swing but, when operating over mineralized soil containing hot rocks it is actually normal - the earth's magnetic field also plays a role. I have learned to listen to the length of a signal and its abrupt start and cut off to tell me if there is a real target or not. The bottom line, a PI is a beast with it's own character.......
