Recent content by obj

  1. O

    ADS-B DIY Antenna

    All speeds in the messages themselves are in imperial, and the data fed to FlightAware is in imperial, so I doubt this is it. (And if it was, I'd expect it to happen consistently for every aircraft you see..) However note that speeds can be either airspeed or ground speed; the data fed to...
  2. O

    ADS-B DIY Antenna

    No, that's an unmaintained version with experimental changes, like it says. Use this one: https://github.com/mutability/librtlsdr/tree/pi-package This is the package distributed on repo.mutability.co.uk; it is just osmocom + debian packaging based on wheezy-backports, built for Raspbian. If...
  3. O

    ADS-B DIY Antenna

    The version of librtlsdr that I package, unless you need something from another version, in which case you should use another version :)
  4. O

    ADS-B DIY Antenna

    It uses whatever shared library the dynamic linker picks up, so yes, potentially there is a difference there. You can make it use a specific version by setting LD_LIBRARY_PATH. "ldd `which dump1090-mutability`" will tell you what it's using.
  5. O

    ADS-B DIY Antenna

    It's to reduce the chance that dump1090 starts dropping samples if there is other stuff running that's competing for CPU. For example it helps while you're running a package upgrade or similar. If the package upgrade is short on CPU it just runs a bit slower. If dump1090 is short on CPU then you...
  6. O

    ADS-B DIY Antenna

    It's complicated! I only worked out exactly what was going on recently. There are three stages of controllable amplification in the dongle: the LNA, the mixer, and the IF VGA - that amplify the signal, in that order. When you set manual gain, that sets the LNA and mixer gain to max, and sets...
  7. O

    ADS-B DIY Antenna

    Yep, that looks fairly normal.
  8. O

    ADS-B DIY Antenna

    node is a javascript engine, already not python? :)
  9. O

    ADS-B DIY Antenna

    FWIW, "agc" is identical to -10 (if you say "agc", the init script turns that into --gain -10 !) AGC seems to be a good choice for unamplified antennas at the moment - it is not the autogain part that it useful, it's that the total gain in that configuration is actually slightly higher than...
  10. O

    ADS-B DIY Antenna

    It's a function of the package upgrade, not the reconfiguration. The javascript/html are marked as "config files" so that user modifications are preserved. They don't actually hold config information and they are not touched by dpkg-reconfigure at all. When a new version of a package is...
  11. O

    ADS-B DIY Antenna

    They are only updated in --oversample mode (and, obviously, only if you're running with a real dongle). see demod_2400.c. Noise power collection is currently disabled because it was more expensive, cpu-wise, than I was happy with. (but the stats hooks are still there). Per-message RSSI is passed...
  12. O

    ADS-B DIY Antenna

    What, 500+MB of signal stats? What did you set the reporting interval to ?! The default settings generate only about 0.3MB per day.
  13. O

    ADS-B DIY Antenna

    You didn't let dpkg update the javascript when you upgraded. Please run: sudo apt-get -o Dpkg::Options::="--force-confask" --reinstall install dump1090-mutability and when it asks if you want to install the package maintainer's new version of the various javascript files, SAY YES.
  14. O

    ADS-B DIY Antenna

    Don't know about node, but it's fairly normal for dump1090 to be high CPU. The demodulator has a lot of heavy lifting to do. Merely receiving the sample data over USB takes about 8%, and that's before anything is done with the data. My dump1090 processes regularly run at 35-45%. It would only be...
  15. O

    ADS-B DIY Antenna

    What's in the log file? It should not be anything like that big, unless you turned on the "log all message" option (which does warn you it'll be big!)
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