I think I found the location of the Baltic Jammer. In Kaliningrad, Russia.

Since Dec 15 aircrafts have suffered from navigation errors over south Baltic Sea, on and off.

By plotting an assumed max jamming-range for each bad position there is one area standing out: Kaliningrad. pic.twitter.com/EgT6mcoZU4

— Markus Jonsson (@auonsson) January 3, 2024