One of the small problems which encounter the initial researchers, (as certain experienced researchers) in the analysis of the targets, is the interpretation of a good signal " almost ", with a " outward journey and return " (its good in sweeping and in the two directions right-hand side-left), but which appear odd all the same.... so to speak, not frankly of the collar! In fact in a zone with nails, they can quite simply be two nails surrounded by their halation, and moved away from a score of centimetres. These two targets " hang " discrimination either because of the oxide halations, or because deep, they make think of only one " non-ferrous " target. The sound then heard, though a little erratic, creates a doubt which must be checked. A deep non-ferrous target will give the same type of sound (I know, I repeat itself) but if I insist, it is all bonnement because a number among us made the following experiment: you prospect a place and one of your colleagues more tested passes behind you (just in your traces) and the currency comes out you which you would have liked to count in your collection! The only manner of curing that is correctly to analyze the targets. We recommend the following method: - to dig oval holes The beginners in general have a clear tendency to make a round hole way " well ", right under the target, whereas with detectors of the " dynamic " type it is more effective to dig a " oval " to be able to operate its head of detection of left to discriminate on the right. In a " trou/puits " it is very difficult to analyze a target, and this is why two nails rusted apart 20-25 cm can easily be taken for a good target! Thus make holes quite broad and not inevitably deep when you have a doubt; you will gain there much time and of efforts, believe me. In " ovalizing " the holes, one often reduces the problem referred to above. If however the doubt persists, practise the method of the cross: sweep Is / Western and also North-South, you will have a good luck of anuler one of both target which is undesirable. Always in case of doubt, your angle of analysis, you compared to the axis of discovered object place perpendicularly change, in a case it will be can be discriminated, in the other less or it is necessary to assemble the discri for the same result!