Today I noticed that since June 18 my PiAware AGC halted scanning and stuck on max gain, 58.6 dB. See screen shot attached. My AGC gain was typically more around 49.6 dB. This is where it has now reset to after restarting dump1090. But I’m curious, anyone have any ideas as to why this may have happened, or seen something similar?
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What are outputs of following commands?
sudo piaware-config -show rtlsdr-gain
sudo piaware-config -show adaptive-dynamic-range
sudo piaware-config -show adaptive-burst
sudo piaware-config -show adaptive-max-gain
sudo piaware-config -show adaptive-min-gain
For yor guidance my outputs are shown in sccreenshot below.
Your output may be different based on your settings.
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I don’t have burst mode set as I do not get a lot of nearby traffic, but a lot of distant traffic.
More data showing the agc gain jump on June 18, stuck at max, and then back down to normal after I rebooted today.
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I had the same thing happening, the auto gain function is not reliable it seems. I had to bounce through the options to stop auto gain, including setting both max and min gain at 49.6. Even then, it slammed the gain up to the max/58db and slammed it down to around 40.
We need a more reliable way to set the gain via the site configuration menu. Sure would be easier that way. Rant Closed.
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Did you find a fix for this? I started seeing this all of a sudden as well:
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I just rebooted dump1090 and gain seems to have stabilized back as it was, 49.6.
I never had this chronic up and down that you are seeing. Although, yours also now seems to have stabilized at 49.6. Where was it usually before this started?
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So, it’s happened again, exact same issue.
“adaptive: reached upper gain limit, halting dynamic range scan here”
And there it stays, stuck at 58.6 dB.
I have added “adaptive-dynamic-range no” to the piaware boot config.txt file, and set gain to 49.6, so this won’t happen again.
This is clearly an agc bug. Does anyone at FA monitor this forum?
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I had to set the Adaptive Gain max and min to the same value, 49.6. It seems to behave a bit better. The code seems to react to impulsive local signals and drops the gain immediately. Then it takes way too much time to adapt to the desired values after the local traffic is gone. It is a band-aid to fix the max and min values, but the only way to stop this slam/bam gain mess.
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Or, add “adaptive-dynamic-range no” to the piaware boot config.txt file, which disables agc completely. Then set gain to whatever.
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Does it entirely stop logging about adaptive gain at that point? It’s meant to re-probe for lower gain periodically (well, or more specifically, if available dynamic range drops it’s meant to drop gain)
it would be useful to know the contents of the “adaptive” section of stats.json when you’re having the problem.
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Yes, it entirely stops logging/scanning. It’s the last entry no matter how long ago, and the gain stays stuck at max.
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Also, don’t know if you saw the log screenshot in my first post, if that helps?
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I did, but I didn’t know when that was captured, hence the question.
Can you get a copy of stats.json when it’s failing? (From /run/dump1090-fa)
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To do that I guess I’ll have to edit the config file again to re-enable agc, and then wait for it to reoccur. Will advise.
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My receiver works on adaptive gain as designed:
sudo journalctl -u dump1090-fa -n 20 | grep adaptive
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Yes, so did mine for a year, then, not (I made no changes).
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(1) Which config file you edit?
If you are using piaware SD card image, you have to edit boot/piaware-config.txt. Editing file /etc/default/dump1090-fa is ineffective as changes made will be lost on reboot.
If you are using vanila Raspberry Pi OS image with package install of piaware and dump1090-fa, you have to edit file /etc/default/dump1090-fa
(2) After making and saving changes, you have to reboot Pi, or restart piaware and dump1090-fa.
(3) In case of piaware sd card image, please open file /etc/default/dump1090-fa and check if all gain settings you made in file /boot/piaware-config.txt are incorporated by system into this file as well.
I’ve done all that, I edited the boot config, and all my settings are as specified and current. There’s nothing wrong with my config. As I have it now it’s fixed at agc = no and gain = 49.6. The problem arises when I have agc = on. To get the stats.json when the problem arises as requested, I will change my config back and wait for it to happen again (could be a few weeks as before).