[Pisces]

It is possible that the other contacts are too far away, or simply too silent, or hidden behind a seamount.

Are you below or above a layer? What is your depth in relation to the soundlayer profile. And what is the possibility of them being below a layer.

Have you selected the TA as the input to the broadband waterfall? (it's not by default upon entering the game) Do you get 'symmetric' ownship lines in a turn? When you are running straight the ownship TA lines should be hidden in the deaf-zone that surrounds your course/bow. So normally you shouldn't hear yourself on the TA.

How have you set the Time average switches of the upper and lower waterfall displays. The short-term selection makes the signal drop quicker, but faint signals won't show. Longer-term signals get summed up over a longer time, so stand out brighter. But this takes a while for new pixels lines to be shifted down and generated.