https://discussions.flightaware.com/t/why-not-use-64-bit-os-on-rpi-model-3-and-4/81404#installation
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One more question; has anyone noticed a decreased receiver performance when feeding multiple sites? After my SD card cashed in they chips, I rebuilt with all the latest versions, which seamed to work just fine. So, I tried to re-add a feeder to Flightradar24 and PlaneFinder. I noticed this build isn’t receiving an many aircraft as before. I also can compare it to my other receiver at my house about 10 miles away. Currently my home is reporting over 1800 hits today and the new site is only reporting 1300 when it should be reporting more than 2000 flights today. (It’s bluebird weather here today so there are a bunch on GA aircraft in the air along with the heavies)
Not sure what’s going on but I don’t like it that the rebuilt receiver (no changes to the antenna system) is missing so many flights.
So, what am I missing or has the new feeders messed up Piaware 7.1?
Thanks,
Eric
I have no idea, they were always built with default settings. I never went in and tweaked any hardware settings.
Eric
Previous default setting was gain -10 which set the gain to slightly more than 55 dB.
Current default setting is 60 which also sets gain to skightly more than 55 dB, so the old & new defaults are same thing.
However from ver 6, a new thing has been introduced which dynamically adjusts the gain. This us calle “adaptive gain control”.
Please post output of following command which will show how this “sdaptive gain control” is adjusting your gain.
sudo journalctl -u dump1090-fa -n 10
Here is the dump from that previous command:
pi@piaware : ~ $ sudo journalctl -u dump1090-fa -n 10
– Journal begins at Wed 2022-01-12 19:03:21 UTC, ends at Fri 2022-02-04 23:52:>
Feb 04 23:11:25 piaware dump1090-fa[435]: rtlsdr: tuner gain set to 1.4 dB (gai>
Feb 04 23:11:35 piaware dump1090-fa[435]: adaptive: available dynamic range (41>
Feb 04 23:21:26 piaware dump1090-fa[435]: adaptive: available dynamic range (29>
Feb 04 23:21:26 piaware dump1090-fa[435]: adaptive: changing gain from 1.4dB (s>
Feb 04 23:21:26 piaware dump1090-fa[435]: rtlsdr: tuner gain set to 0.9 dB (gai>
Feb 04 23:21:36 piaware dump1090-fa[435]: adaptive: available dynamic range (43>
Feb 04 23:31:27 piaware dump1090-fa[435]: adaptive: available dynamic range (28>
Feb 04 23:31:27 piaware dump1090-fa[435]: adaptive: changing gain from 0.9dB (s>
Feb 04 23:31:27 piaware dump1090-fa[435]: rtlsdr: tuner gain set to 0.0 dB (gai>
Feb 04 23:31:37 piaware dump1090-fa[435]: adaptive: available dynamic range (43>
lines 1-11/11 (END)
OOPS, my ssh terminal truncated the output. Here is the whole output: – Journal begins at Wed 2022-01-12 19:03:21 UTC, ends at Fri 2022-02-04 23:56:14 UTC. –
Feb 04 23:11:25 piaware dump1090-fa[435]: rtlsdr: tuner gain set to 1.4 dB (gain step 2)
Feb 04 23:11:35 piaware dump1090-fa[435]: adaptive: available dynamic range (41.6dB) >= required dynamic range (30.0dB), stopping downwards scan here
Feb 04 23:21:26 piaware dump1090-fa[435]: adaptive: available dynamic range (29.1dB) + half gain step down (30.0dB) < required dynamic range (0.5dB), starting downward scan
Feb 04 23:21:26 piaware dump1090-fa[435]: adaptive: changing gain from 1.4dB (step 2) to 0.9dB (step 1) because: dynamic range fell below target value
Feb 04 23:21:26 piaware dump1090-fa[435]: rtlsdr: tuner gain set to 0.9 dB (gain step 1)
Feb 04 23:21:36 piaware dump1090-fa[435]: adaptive: available dynamic range (43.0dB) >= required dynamic range (30.0dB), stopping downwards scan here
Feb 04 23:31:27 piaware dump1090-fa[435]: adaptive: available dynamic range (28.5dB) + half gain step down (30.0dB) < required dynamic range (0.9dB), starting downward scan
Feb 04 23:31:27 piaware dump1090-fa[435]: adaptive: changing gain from 0.9dB (step 1) to 0.0dB (step 0) because: dynamic range fell below target value
Feb 04 23:31:27 piaware dump1090-fa[435]: rtlsdr: tuner gain set to 0.0 dB (gain step 0)
Feb 04 23:31:37 piaware dump1090-fa[435]: adaptive: available dynamic range (43.9dB) >= required dynamic range (30.0dB), stopping downwards scan here
Gain set to ZERO 
You should recieve ZERO number of aircraft.
Something is wrong! 
@obj may shed some light.
EDIT:
As you are using piaware SD card image, You can turn-off adaptive gain by following command:
sudo piaware-config adaptive-dynamic-range no
sudo systemctl restart piaware
After 10 minutes check logs
sudo journalctl -u dump1090-fa -n 10
To check what default value of gain is set (it should output “max”):
sudo piaware-config -show rtlsdr-gain
No.
I am feeding several sites and reinstalled my devices countless. Never had any issues likethat
Yeah, this is unusual. What’s the hardware?
(It looks almost like you have intermittent very loud interference)
So, I’ve ran it a while and it looks like the gain is still jumping around. Sometimes at Gain Step 11, and others times, like this dump, with Gain Step 3. Not sure if I’m looking at the wrong value. Regarding interference, this receiver is on a mountain top in a radio site. While this particular site doesn’t have any 900MHz equipment, I not sure what is in the county radio site 1/4mile away. Although the county doesn’t use any 900MHz frequencies, other government agencies might also be in there. Could also be poor CATV / Internet equipment which also goes through the site.
Here is the latest gain dump:
– Journal begins at Wed 2022-01-12 19:03:21 UTC, ends at Sat 2022-02-05 19:36:00 UTC. –
Feb 05 19:11:14 piaware dump1090-fa[6086]: rtlsdr: tuner gain set to 7.7 dB (gain step 5)
Feb 05 19:11:24 piaware dump1090-fa[6086]: adaptive: available dynamic range (36.2dB) >= required dynamic range (30.0dB), stopping downwards scan here
Feb 05 19:21:14 piaware dump1090-fa[6086]: adaptive: available dynamic range (22.7dB) + half gain step down (30.0dB) < required dynamic range (4.0dB), starting downward scan
Feb 05 19:21:14 piaware dump1090-fa[6086]: adaptive: changing gain from 7.7dB (step 5) to 3.7dB (step 4) because: dynamic range fell below target value
Feb 05 19:21:14 piaware dump1090-fa[6086]: rtlsdr: tuner gain set to 3.7 dB (gain step 4)
Feb 05 19:21:24 piaware dump1090-fa[6086]: adaptive: available dynamic range (38.3dB) >= required dynamic range (30.0dB), stopping downwards scan here
Feb 05 19:31:14 piaware dump1090-fa[6086]: adaptive: available dynamic range (25.4dB) + half gain step down (30.0dB) < required dynamic range (1.0dB), starting downward scan
Feb 05 19:31:14 piaware dump1090-fa[6086]: adaptive: changing gain from 3.7dB (step 4) to 2.7dB (step 3) because: dynamic range fell below target value
Feb 05 19:31:14 piaware dump1090-fa[6086]: rtlsdr: tuner gain set to 2.7 dB (gain step 3)
Feb 05 19:31:24 piaware dump1090-fa[6086]: adaptive: available dynamic range (39.9dB) >= required dynamic range (30.0dB), stopping downwards scan here
Do you have a filter connected between Antenna and the Dongle?
If not, better connect one.
For 1090 MHz Only (narrow-band)
For 1090 and 978 MHz (wide-band)
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Till you get and install a filter, put a lower limit to adaptive gain
sudo piaware-config adaptive-min-gain 30
sudo systemctl restart piaware
Now check/confirm minimum gain has been set to 30 dB
sudo piaware-config -show adaptive-min-gain
After 10 minutes check logs
sudo journalctl -u dump1090-fa -n 10
I am using the FlightAware Pro Stick Plus for my receiver. I was under the impression it had all the filtering I needed. BTW, it’s not a case of the receiver not working at the site, it’a about the receiver not working as well as it did before I upgraded the OS and feeder application. It was working rather well, at least that is what I thought, comparing my data collection compared to nearby stations.
I think I want to let it run for at least 24 hours to allow the data to smooth out. I’ll go ahead and change the min gain but like I said earlier, none of this happened until I updated the software.
Eric
I live in an urban high-rise area with all sorts of RF noise (FM, TV VHF, UHF, Cell phones etc). In RF noisy conditions like mine and many others, the internal filter of ProStick Plus is not enough, and an external filter is required.
Please see this post where I have posted results of RF Scan at my location without and with external filter. This scan covers the full frequency range of the dongle (24 MHz ~ 1800 MHz).
https://discussions.flightaware.com/t/signal-level-randomly-changing/80309/7
Since the major change in software is addition of “Adaptive Gain Control”, first disable it, then monitor for 24 hrs. Afte that, you can enable adaptive gain control and again monitor for 24 hrs
sudo piaware-config adaptive-dynamic-range no
sudo systemctl restart piaware
sudo systemctl restart dump1090-fa
NOTE: After disabling “adaptive gain control” by 1st command above, you must either reboot Pi or restart both piaware and dump1090-fa for the change to be implemented
After 10 minutes check logs
sudo journalctl -u dump1090-fa -n 10
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I need additional filtering here. The internal filter in the ProStick Plus is not enough here.
See this earlier post from a few years ago:
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Before I make any hardware changes, I wanted to share 2 screen shots. One is the mountain top site that, prior to Monday, has an awesome coverage area but, since installing SkyAware 7.1, sucks. The second image is at my house about 10 miles away and 1200’ lower in elevation which historically received a couple hundred less aircraft a day.
As you can see, something isn’t right with the configuration. Maybe I should hose the other 2 feeders and see if that changes anything???
Thanks,
Eric
OK, uninstall other two feeders and observe the performance. It will clear if the cause of problem is those feeders or something else.
What are the commands/routines I should use to remove FR24 and PlaneFinder from the system (or would I be better in building a new, clean image)?
What version did you upgrade from?
Was it version 6 or something older?
Auto gain was introduced in version 6 so, if the problem might be caused by the auto gain feature , if you have local interference that is triggering it. If your previous version was Version 5 or older it would have been operating with a fixed gain.
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