HI got new joey coil and did some testing. put a quarter on the ground then put a 4in old dug nail right on top of it. I swept the coil over the full length of coin and nail, machine went silent nulled out every pass. then i turned 90 degrees and swept it again loud and clear sweet sound every time. next time i get a null detecting i will try it from different angles to be sure. I am sure i missed a few coins because of the null thought it was just iron did not know that maybe something could be under it if you sweep from different angles.Still learning the explore, went to local park to try out new coil got several nice hits but ground is solid yet so will come back soon can not wait. harry