I've read that opensky is applying advanced filtering algorithms but what's wrong here with this station's high amount of filtered messages?
What can I do to improve the performance of the station.
Config is:
Raspi 3, Raspian Stretch, dump1090-fa, FA Prostick and FA Prostick Antenna, Gain @43.9 (max messages/positions/AC)
A second Raspi3 with same SW but with an RTL-SDR and LNA has 0% filtering and nice message rate (but also no Mode-A/C messages).
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 4501147 [ 91%] filtered (681.99 /s, 445.10 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 2874482 [ 58%] Mode-S filtered (435.53 /s, 423.66 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 4929081 unsynchronized frames
journalctl -b 0 -u opensky-feeder
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: Statistics
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - started on Mon Jun 11 10:00:21 2018
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - running since 0d, 01h:50m:00s
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: Receiver
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 4929081 frames received (746.83 /s, 504.48 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 1626665 [ 33%] Mode-A/C (246.46 /s, 21.44 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 2345461 [ 48%] Mode-S Short (355.37 /s, 346.69 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 956955 [ 19%] Mode-S Long (144.99 /s, 136.35 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 730233 [ 22%] type 0 (110.64 /s, 106.31 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 209637 [ 6%] type 4 (31.76 /s, 31.96 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 28803 [ 1%] type 5 (4.36 /s, 3.77 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 1376788 [ 42%] type 11 (208.60 /s, 204.65 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 35585 [ 1%] type 16 (5.39 /s, 4.68 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 426195 [ 13%] type 17 (64.58 /s, 59.16 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 1739 [ 0%] type 18 (0.26 /s, 0.22 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 372563 [ 11%] type 20 (56.45 /s, 54.41 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 120806 [ 4%] type 21 (18.30 /s, 17.87 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 67 [ 0%] type 24 (0.01 /s, 0.01 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 [ 0%] status (0.00 /s, 0.00 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 [ 0%] unknown (0.00 /s, 0.00 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 4501147 [ 91%] filtered (681.99 /s, 445.10 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 2874482 [ 58%] Mode-S filtered (435.53 /s, 423.66 /s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 4929081 unsynchronized frames
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: Buffer
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 queued messages (current)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 22 queued messages (max)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 discarded messages (current)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 discarded messages (overall)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 discarded messages (in worst overflow situation)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 199 messages in pool (Usage 0.00%)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 dynamic pools (current)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 dynamic pools (overall)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 dynamic pools (max)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 1 flushes
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 uncollected dynamic pools
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 Garbage Collector runs
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: Network
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - currently online
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 6600 [100%] seconds online (overall)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 0 disconnections
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 1 connection attempts
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 9877911 bytes sent (1496.65/s)
Jun 11 11:50:21 raspi3 openskyd-dump1090[8500]: - 8 bytes received (0.00/s)
the other stats block in the log look similar (for filtering values).