I Just recorded a signal using SDR++ and RTL-SDR.
The signal seems to be normal audio but I cannot extract clear audio from it.
I can recognize speech and tones even without any demodulation so I think it should be an AM modulation but AM demodulation doesn't give me a clear audio.
I also tried NFM and got the same results (unclear audio)
Here is baseband record:
the signal is on the 139.188 MHz
Can anyone help me and give me some hints on identify this signal and how extract a clear audio from it?