The signal reports don't make any sense, right? They are negative numbers (unless you are running QRO...but let's not go there), yet the signals are clearly audible. The number represents the strength or your FSK signal (6.25 Hz) as it compares to the signals in an entire 2.5 kHz SSB bandwidth. I was curious about the math, and I combed the internet looking for an explanation. Here's the actual math behind the report: http://www.arrl.org/forum/topics/view/1957 Keep in mind that the noise floor is relative to the receiving station. The equations explain why FT8 signals start decoding at -26db - everything else is below the noise floor: SNRFSKFT8 = SNRreportedFT8 + (10 x LOG (2500 Hz/6.250 Hz)) SNRFSKFT8= SNRreportedFT8 + (10 x LOG (400)) SNRFSKFT8 = SNRreportedFT8 + 26 dB Given that 1 S-unit = 6db, I put together the following table to help understand what your 'real' signal report would be. It's surprising that the stations running QRO and getting +10 reports are really only an S6 above the noise floor.