The cause here for that was using Ref Spec instead of Flatten . I chased it for weeks, it has no effect on decoding, but produces silly high SNR if below 400 Hz or so. Simply uncheck Ref Spec in the Waterfall controls, and go back to "Flatten" and I bet the problem goes away. 73, N0AN Hasan
On Sat, Oct 16, 2021 at 12:03 AM Black Michael via wsjt-devel < wsjt-devel@lists.sourceforge.net> wrote: > I can see the opposite possibility in this data. Looks like below 300 the > levels are low, high from about 300-400, then pretty consistent > Red line here is 50-point moving average of 5000 points. Above 2200 we're > getting into the region where bandpass limits might have an effect of some > sort (lack of noise or perhaps more likely to have higher power > transmitters?). > > [image: Inline image] > > Mike W9MDB > > > > > On Friday, October 15, 2021, 11:45:16 PM CDT, Rich - K1HTV via wsjt-devel < > wsjt-devel@lists.sourceforge.net> wrote: > > > Has anyone experienced exaggerated dB signal reports given by WSJT-X to > decoded FT8 signals of stations transmitting tone frequencies below 500 Hz? > I use a K3 with 2.8 KHz filter using WSJT-X Version 2.5.0 . I have also > seen this in earlier versions. > > When stations using low audio tones are decoded, the signal levels that > WSJT-X gives them far exceeds the levels given to signals with higher > frequency tones of equal intensity level observed visually on the wide > graph. > > I have run the “Measure Reference Spectrum” tool on a quiet frequency and > have the “Ref Spec” checkbox on the Wide Graph checked. This didn’t resolve > the noted anomaly. I first observed this on Foxes running 3 or 4 streams > using tones below 500 Hz with the lower tones appearing a few DB stronger > than the higher tones. > > Any idea as to why this may be happening. > > 73, > > Rich – K1HTV > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel >
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