The 1090MHz filters arrived and i measured this variant plus one without filter.
Closer to the filter the response looks quite ok:
Far away from the passband the supression degrades. Especially very high frequencies pass the filter quite well.
This is the assembly with 47pF capacitors and a 27nH coil for supply of the MMIC. Below 200MHz does not pass the capacitors well. There is even some remaining gain at 3.4GHz although its a 1.6mm thick FR4 PCB.