Hi!
Is it really possible that I got continous messages from a plane at this distance and altitude (started at 40000 ft)? Of course it is an MLAT-Flight, but the message counter got up all the time. I have free sight this direction and I got more than this one with similar distances but in the same direction.
Just wondering.
That is a bit odd. There is a grace period where you’ll continue to receive mlat results even if your receiver hasn’t contributed to results recently, since it’s pretty random whether your data is used for a particular solution or not, but that is not particularly long and doesn’t explain such a long trace. I don’t see a solution near that point in the screenshot that included any of your receivers, the last was 40 mins earlier, so there might be something going wrong there.
The track itself looks correct.
Potentially you can have better range with mlat than with ADS-B, as mlat can be done from a single 56-bit message while an ADS-B position needs a pair of 112-bit messages reasonably close together.
Maybe that will explain it… Because at this direction there are really no remarkable mountains between Vienna and the Netherlands. 
And the altitude was 40000 ft most of the time. So the ModeS Messages I saw could be real? Right?
