There is no drift as such. The receiver however shows significant thermal dependence.
- Window closed, everything stable, room temperature stable resulted in no drift.
- Window open, room temperature sinking, drift kicks in between 0340 and 0610 a 20Hz drift is observed (IQ4DJ MEPT).
The problem could probably be solved by adding an oven. For me this thermal behaviour is understood well enough to just don't care about. My HF-3 will remain as is.
BTW, the jumps did not reoccur.