quimby
Contributor
cudachaser:In Cape Canaveral...we are trying to develope passive acoustics....an ear that listens...no active sonar
Joe
30+years ago they called it the " SOSUS (SOund SUrveillance System)". Just ask the navy and CIA how they found (heard) the Russian sub that broke up in the Pacific and we tried to pick it with the "glomar explorer" from 17000ft
3DENT
If you heard it, it you weren't being tracked. Sonar in the audio range doesnt have the resolution to pick up small targets
Your right as the discrimination ability of a unit is dependant on freq and pulse length.
What you hear or feel isnt the "Tone" or xmitted frequency, its the pulse rep rate, and if your up close you'll feel the snap like a arc from a spark plug or similar. Im talking small systems like commercial grade side scans or forward searching or even depth finders with some punch.
All bets are off if we get into phased array and cont FM and fancy stuff but the above stands for the usual pulsed sonar units