Adaptive Gain - pegs at 60dB?

[furkly]

Hi all!

Thanks for everything you do to help on this forum - it has been a wealth of knowledge getting everything setup. I've managed to expand from 40nm to 75nm just with the tips in here and looking for more gains (heh).

I installed graph1090, and noticed that dB seems to be pegged at 59dB. Is this typical?

hardware
- RTL-SDR V3
- A3 ADS-B antenna from jetvision (+5Bi)

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systemctl status dump1090-fa

 pi@pi24-bookworm:/var/log $ sudo systemctl status dump1090-fa
● dump1090-fa.service - dump1090 ADS-B receiver (FlightAware customization)
     Loaded: loaded (/lib/systemd/system/dump1090-fa.service; enabled; preset: enabled)
     Active: active (running) since Tue 2024-02-13 10:27:06 UTC; 1h 52min ago
       Docs: https://flightaware.com/adsb/piaware/
   Main PID: 126942 (dump1090-fa)
      Tasks: 3 (limit: 3919)
        CPU: 15min 13.166s
     CGroup: /system.slice/dump1090-fa.service
             └─126942 /usr/bin/dump1090-fa --quiet --device-type rtlsdr --gain 60 --adaptive-range --fix --lat -35.2821 --lon 149.1547 --max-range 360 --net-ro-port 30002 --net-sbs-port 30003 --net-bi-port 30004,30104 --net-bo-port 30005 --json-location-accuracy 1 --write-json /run/dump1090-fa

Feb 13 10:27:06 pi24-bookworm systemd[1]: Started dump1090-fa.service - dump1090 ADS-B receiver (FlightAware customization).
Feb 13 10:27:06 pi24-bookworm dump1090-fa[126942]: Tue Feb 13 10:27:06 2024 UTC  dump1090-fa 9.0 starting up.
Feb 13 10:27:06 pi24-bookworm dump1090-fa[126942]: rtlsdr: using device #0: Generic RTL2832U OEM (Realtek, RTL2838UHIDIR, SN 00000001)
Feb 13 10:27:06 pi24-bookworm dump1090-fa[126942]: Found Rafael Micro R820T tuner
Feb 13 10:27:07 pi24-bookworm dump1090-fa[126942]: rtlsdr: tuner gain set to about 58.6 dB (gain step 29) (tuner AGC enabled)
Feb 13 10:27:07 pi24-bookworm dump1090-fa[126942]: adaptive: using 50% duty cycle
Feb 13 10:27:07 pi24-bookworm dump1090-fa[126942]: adaptive: enabled adaptive gain control with gain limits 0.0dB (step 0) .. 58.6dB (step 29)
Feb 13 10:27:07 pi24-bookworm dump1090-fa[126942]: adaptive: enabled dynamic range control, target dynamic range 30.0dB
Feb 13 10:27:17 pi24-bookworm dump1090-fa[126942]: adaptive: reached upper gain limit, halting dynamic range scan here
​

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graph1090
1.png

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[abcd567]

Flightaware 1090 Antenna → Flightaware 1090 Filter → Flightaware ProStick Plus (Blue) → OrangePiPC → 32-bit Armbian Bookworm → dump1090-fa ver 9.0

dump1090-localhost-misc-24h-3.png



35e5bcf7efab6a890212020b830e34ec8e83ae13.png




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[furkly]

Yeah ok - similar but I've got burst off. I'll let it run for a couple of days and see.

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