Regarding Observation 11595065 …
This observation is shifting: strangely in the previous one I was able to have it centered
Regarding Observation 11590577 …
Is my antenna doing something wrong?
Due to Doppler effect, the signal is shifted in frequency based on the relative velocity between the satellite and your ground station. This shift can be predicted when the satellite orbit is well known (often in the form of a “TLE” - two-line-elements). Your SatNOGS station performs this prediction and tries to correct the Doppler shift (shifted to higher frequency at the beginning of the pass when traveling towards the stations, shifted to lower frequency at the end).
When the signal is not transmitted from an object in the expected orbit, the prediction is wrong and you will see a residual frequency shift, this is what is happening here.
If the transmitter is stationary with regards to your ground station, the residual shift will be exactly the opposite to the predicted shift, this seems to be happening in your first observation.
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