Hi Jos There isn't a limit for the amount of Doppler shift that can be compensated. We use the same corrections for DL0SHF 24GHz beacon where the Doppler shift is frequently much higher than 19kHz without problems.
I think the sked frequency can only get changed after a readback from the radio, or operator input, as we discussed on the other forum. No further thoughts at the moment, I'm afraid. 73 Charlie On Fri, 27 Sept 2024 at 16:50, Jos F.M. VanderList via wsjt-devel < wsjt-devel@lists.sourceforge.net> wrote: > Good afternoon all, > While monitoring the DL0SHF beacon at 10 GHz I noticed strange behavior of > the Doppler tracking. > I set the sked frequency initially to 10368.024 MHz, with Doppler tracking > "On DX Echo". > DL0SHF appears initially at its normal place in the waterfall. > However, when the (absolute) value of the DX Doppler exceeds approximately > 19 kHz the sked frequency gets changed in the Astro window, without me > touching anything. The change is steadily downward with 1 or 2 Hz at a > time. At the same time the VFO frequency of the transceiver is also ordered > to a lower frequency. And the result is that the beacon is drifting slowly > upwards in the waterfall. > I also noticed that in the situation that WSJT-X alters the sked frequency > it is sometimes possible to adjust the sked frequency by turning the tuning > knob of the transceiver, without pressing CTRL. > Mike, W9MDB, checked the communication between WSJT-X and the transceiver > and he didn't find anything strange there. So to me it seems that the > problem is in WSJT-X itself. > Before anyone asks: all my oscillators are locked to my 10 MHz GPSDO. > And the transceiver frequency follows the frequency ordered by WSJT-X. > I'll give some examples from this afternoon. Sked frequency is the sked > frequency in the Astro window. Transceiver frequency is the frequency as > shown below the Monitor button in the main WSJT-X window. And DXDop is as > shown in the Astro window. > DXDop: TRX freq.: Sked freq.: > -17000 10368.007000 10368.024000 > -18000 10368.006000 10368.024000 > -19116 10368.004877 10368.023993 > -19500 10368.004232 10368.023932 > -19999 10368.003480 10368.023479 > -20497 10368.002335 10368.022832 > Can anyone shed some light on this? Why is WSJT-X altering the sked > frequency if the Doppler is more than 19 kHz? And why isn't the Doppler > tracking keeping the beacon stable in the waterfall? Is it a bug, am I > doing something wrong, is my understanding of the Doppler tracking wrong? > 73, Jos, PA0JOZ > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel >
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