It took 36 weeks, but worth waiting for: a real postcard QSL confirming my reception of NDB MIQ-426 “Mike for Ingolstadt”. I sent my report to DFS (Deutsche Flugsicherung) in Langen, Germany. The beacon is located south of Ingolstadt, and you can actually see it driving on highway A9 between München and Ingolstadt (east of the highway).
Not sure where the “for Ingolstadt” comes from. The beacon is close to Ingolstadt airport. But it is not aligned with the runways and serves as a high and low level enroute navigation beacon according to ourairports.com .