In Reply to: RE: People here keep acting as if it is simple to hear a -120dB down signal. posted by Tony Lauck on September 12, 2014 at 07:54:30:
"...it is possible to hear single tones that are as much as 20 dB below the broadband noise floor."
That's why I used Morse Code as a HAM Radio operator when I was a kid. One could audibly decode a series of weak dots and dashes (approx 1KHz tones) in the noise floor where normal voice transmissions would be unintelligible.
Additionally, the audio bandwidth required for voice transmission (SSB) was about 2KHz so 2KHz bandwidth filters were used. Dropping the filter bandwidth also improved signal-to-noise ratio, dropping broadband noise by nearly another 10dB by using narrow filters CW (Morse Code) vs ~2KHz for SSB voice.
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Follow Ups
- RE: People here keep acting as if it is simple to hear a -120dB down signal. - AbeCollins 11:14:42 09/12/14 (0)