Hi, I realize air testing is not a sure way of measuring depth but does the air test typically give a deeper reading or a more shallow reading? I am asking because it is raining out and I am in the basement with Simplex and Deus 2. Silver half and silver quarter. Basement floor is clean. Simplex is totally quiet prior to test and Deus has a little EMI from something. I can only get 3 inches on each machine before the signal disappears. Is this normal? Thanks!