Image of spectrogram of isolated audio between 400-600hz, dots/dashes visible in spectro - I will work on decoding shortly and update this post with my attempt :
https://i.imgur.com/YPyLmU2.png
Even sharper hi-res spectrogram morse isolate :
https://i.imgur.com/CITtisW.png
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Same image as above but reversed, since it seems there is a theory that the morse is backwards in the original audio :
https://i.imgur.com/ODTDeXz.png
For whatever reason, code appears mainly confided to right audio channel (bottom channel in images above).
Isolated audio between 400-600hz :
https://clyp.it/fxrjbw5r
Lossless .flac upload :
http://www.filedropper.com/102901audio400600iso