There are different versions of dump1090 available. I’m not sure which one you are using but many of us here are having good results with dump1090-mutability. This also has better logging as compared to other versions. Details here: http://discussions.flightaware.com/ads-b-flight-tracking-f21/raspbian-ubuntu-packages-for-dump1090-mutability-available-t19619.html and here: https://github.com/mutability/dump1090
