On the wave scanner you are looking for bars accompanied by a sound like a geiger counter as it scans... <click, click...click click>. If you aren't hearing clicks you are following something else other than a materials node or outcropping (technology, your own ship, whatever, the scanner picks up anything and everything and identifies different types of object mainly by sound but also by waveform). The sound is easy to get, the waveform takes a bit more practice. In the start, the bars on the wave scanner are wide, and the clicks very faint (you'll have to stop to hear them probably), but they get louder and more distinct the closer you get and the better the direction you are facing. Land in between two craters.