The Daxis LNB has no wobble at all and after being plugged in for 8 hours there is only a drift of about 800 Hz so much less than after 2 hours.
maybe because the sun is not shining on the LNB in the evening so a cooler temperature is not so drifty?
Anyway if the Opticum is no better I may as well keep this Daxis.
Image shows drift over 4 mins on a slow waterfall.
It's not so much about the absolute temperature, but about the change in temperature. If there is hot sun shining in an LNB with a black case, and there are some gusts of wind, for example, it can drift quite a bit back and forth, as the sun heats it slightly, and then comes the wind and cools it down a little. If the temperature is stable, its absolute value does not matter that much. I also observed my unmodded LNBs tend to be more stable at night here at my location, but YMMV.