How can one use audacity to measure sonar, for example 53 C sonar?
You question is too vague.
Do you have a recording of sonar?
What are you wanting to measure?
Well, sonar is an auditory phenomena and I want to know if I am near a place using sonar if I can measure it with Audacity using a regular microphone. So that Hz of say 53 C sonar would be visible on the graph.
I am near a place using sonar
You can tell if you were near a place using Sonar. Audacity doesn’t do analysis in real time. So you can record the environment and then take it home and analyze it.
If you can hear it , but others can’t, and it can’t be recorded , consider the possibility of tinnitus.