that's a Ruthless post
Signal to Noise Ratio
this place reminds me of JT65
>JT65 handles very weak signals, just like WSPR, so will get through where voice and PSK31 won’t. It also works many dB below the noise floor, so although you may not be able to hear any signals – they could be there.
when the noise is louder than the signal (below the noise floor)