Hi Jos

It does appear your situation is unique.  As far as I'm aware, the rig
control software within WSJT-X itself has not changed for years, and this
problem has never been reported before. As I mentioned yesterday, WSJT-X
has been used for EME on 24GHz where Doppler shifts often exceed 19kHz.  It
has also been used successfully on 47GHz, so I'm confident that the issue
is not related to the magnitude of the Doppler shift.

I wonder if you have some other radio you could test with? This could be
for example an SDR controlled by software such as HDSDR or SDR Console.
Both of these programs can be connected to WSJT-X,  since they both have
emulators (using a virtual com port connection such as com0com).  Audio can
be routed via virtual audio cables,

Did the data that Mike studied cover the case during which the sked
frequency was changing?

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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