Thanks, everyone for the discussion. The biggest takeaway for me is that I shouldn't use the wide graph to determine the quality of the signal, which helps.
I do have a waterfall display on my IC-7300, but it has nowhere near the resolution of the wsjt-x wide graph so it’s not very helpful either. I’ll be quiet now! :) -Tim KD0GYG > On Jul 11, 2017, at 1:54 PM, James Shaver (N2ADV) <n2...@windstream.net> > wrote: > > If you throw attenuation at the signal and the issue goes away, the cause is > most likely on the receive side. It also helps to have a panadapter > available (something that isn't tied into the AF chain). The waterfall > itself should not be used to determine signal quality. > > 73, > > Jim S. > N2ADV > >> On Jul 11, 2017, at 2:45 PM, Bill Somerville <g4...@classdesign.com> wrote: >> >>> On 11/07/2017 19:12, Tim Carlson wrote: >>> Would you consider that the first signal on the left is being overdriven >>> somewhat? Or is that just a consequence of a stronger signal? Or is it >>> some atmospheric condition causing the signal to spread? >>> >> Hi Tim, >> >> hard to tell but it is all too common for the Tx audio level fed to the rig >> to be too high. This causes non-linearity and will almost certainly widen >> the transmitted signal. The main product of clipping is harmonics but if the >> sender is using the split operating facility that is largely innocuous due >> to the harmonics being above 3000 Hz and attenuated by the rig's Tx SSB >> filter low pass cut off. Still there is no excuse for over driving the audio >> input to the rig and there is a secondary consequence. At each frequency >> shift of the modulation there is a minimal phase discontinuity, we shift the >> phase without a glitch but nevertheless it is a discontinuity. These small >> discontinuities fractionally widen the signal when the audio is correctly >> matched through to the transmitter but over drive widens them considerably. >> This is what you are seeing, a horizontal spike on the waterfall at each >> tone shift. >> >> You must also be careful about attributing blame in these situations, all of >> the above can happen on the receiving side too, so check your own house is >> in order before accusing another of having a poor signal. >> >> 73 >> Bill >> G4WJS. >> >> >> ------------------------------------------------------------------------------ >> Check out the vibrant tech community on one of the world's most >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> _______________________________________________ >> wsjt-devel mailing list >> wsjt-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/wsjt-devel > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
