Just found the answer in another post, thanks Steve: "usually by running 50 tones with no items rejected, which means I really do not need the threshold tone since I hear everything. If I reject any items then I need the threshold to alert me to nulling effects"
******************************************** my old question ********************************************
"Park, Field, and Beach Threshold
Park, Field, and Beach Modes use a simplified type of threshold tone, i.e. a 'reference' threshold. It is a continuous background tone that will blank when a rejected target is detected. "
Am I correct thinking that the word rejected in P, F or B mode means only a notched out target ID? And if the coil is swept over a faint target without any notching out, "threshold" blanking would not happen? And is that the difference in reference and true threshold?
Thanks!