This just means that your SDR is having issues.
If you have it connected via an USB extension, try without.
Otherwise replug it.
But really it might just be a defective SDR.
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I just changed the dongle to another USB port and it’s working (partially).
I am guessing everything is installed properly but the dongle could be deffective? What I don’t understand is that when I only have flightaware installed, there is no problems but when adding FR24, I have this issue…
Here are a few tests I ran after changing the USB port:
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 Thu 2025-05-29 09:38:57 PDT; 10min ago
Docs: https://flightaware.com/adsb/piaware/
Main PID: 3790 (dump1090-fa)
Tasks: 3 (limit: 4762)
CPU: 39.165s
CGroup: /system.slice/dump1090-fa.service
└─3790 /usr/bin/dump1090-fa --quiet --device-type rtlsdr --gain 60 --adaptiv>
May 29 09:41:08 pi dump1090-fa[3790]: adaptive: available dynamic range (25.7dB) < requir>
May 29 09:41:08 pi dump1090-fa[3790]: adaptive: changing gain from 32.8dB (step 17) to 29>
May 29 09:41:08 pi dump1090-fa[3790]: rtlsdr: tuner gain set to 29.7 dB (gain step 16)
May 29 09:41:18 pi dump1090-fa[3790]: adaptive: available dynamic range (26.9dB) < requir>
May 29 09:41:18 pi dump1090-fa[3790]: adaptive: changing gain from 29.7dB (step 16) to 28>
May 29 09:41:18 pi dump1090-fa[3790]: rtlsdr: tuner gain set to 28.0 dB (gain step 15)
May 29 09:41:28 pi dump1090-fa[3790]: adaptive: available dynamic range (28.1dB) < requir>
May 29 09:41:28 pi dump1090-fa[3790]: adaptive: changing gain from 28.0dB (step 15) to 25>
May 29 09:41:28 pi dump1090-fa[3790]: rtlsdr: tuner gain set to 25.4 dB (gain step 14)
May 29 09:41:38 pi dump1090-fa[3790]: adaptive: available dynamic range (30.8dB) >= requi>
rtl_test -t
Found 1 device(s):
0: Nooelec, NESDR SMArt v5, SN: 00000001
Using device 0: Generic RTL2832U OEM
usb_claim_interface error -6
Failed to open rtlsdr device #0.
takayukibru@pi:~ $ rtl_test -t
Found 1 device(s):
0: Nooelec, NESDR SMArt v5, SN: 00000001
Using device 0: Generic RTL2832U OEM
usb_claim_interface error -6
Failed to open rtlsdr device #0.
It’s likely just coincidence.
Could well be that the first issue you saw was due to the incorrect configuration.
Then you fixed the config but the SDR failed.
If you want to rule out user error, use adsb.im as mentioned before.
That’s pretty hard to screw up (as in only use the webinterface to configure stuff).
I appreciate your help but I don’t want to use adsb.im.
If the dongle is working properly, I should be able to fix this, but I don’t know how to. It will just take time but I know that it can be fixed 
I have turned off, changed again the dongle to another USB and now it could be working fine?
rtl_test -t
Found 1 device(s):
0: Nooelec, NESDR SMArt v5, SN: 00000001
Using device 0: Generic RTL2832U OEM
Detached kernel driver
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
[R82XX] PLL not locked!
Sampling at 2048000 S/s.
No E4000 tuner found, aborting.
Reattached kernel driver
I will keep you updated.
It failed again 
rtl_test -t
Found 1 device(s):
0: Nooelec, NESDR SMArt v5, SN: 00000001
Using device 0: Generic RTL2832U OEM
usb_claim_interface error -6
Failed to open rtlsdr device #0.
Did you stop dump1090-fa?
That error usually just means that another program is using the dongle, so rtl_test cannot use it.
dump1090-fa is still running. I need to turn it off?
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 Thu 2025-05-29 12:32:27 PDT; 28min ago
Docs: https://flightaware.com/adsb/piaware/
Main PID: 2022 (dump1090-fa)
Tasks: 3 (limit: 4762)
CPU: 1min 45.543s
CGroup: /system.slice/dump1090-fa.service
└─2022 /usr/bin/dump1090-fa --quiet --device-type rtlsdr --gain 60 --adaptiv>
May 29 12:32:58 pi dump1090-fa[2022]: rtlsdr: tuner gain set to 44.5 dB (gain step 26)
May 29 12:33:08 pi dump1090-fa[2022]: adaptive: available dynamic range (30.4dB) >= requi>
May 29 12:35:39 pi dump1090-fa[2022]: adaptive: available dynamic range (29.7dB) + half g>
May 29 12:35:39 pi dump1090-fa[2022]: adaptive: changing gain from 44.5dB (step 26) to 43>
May 29 12:35:39 pi dump1090-fa[2022]: rtlsdr: tuner gain set to 43.9 dB (gain step 25)
May 29 12:35:49 pi dump1090-fa[2022]: adaptive: available dynamic range (30.2dB) >= requi>
May 29 12:36:03 pi dump1090-fa[2022]: adaptive: available dynamic range (29.7dB) + half g>
May 29 12:36:03 pi dump1090-fa[2022]: adaptive: changing gain from 43.9dB (step 25) to 43>
May 29 12:36:03 pi dump1090-fa[2022]: rtlsdr: tuner gain set to 43.4 dB (gain step 24)
May 29 12:36:13 pi dump1090-fa[2022]: adaptive: available dynamic range (32.4dB) >= requi>
lines 1-20/20 (END)```Why do you try and run rtl_test if everything is working …?
If dump1090-fa is using the SDR … that’s exactly what you want after all.
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I stopped dump1090-fa. Now, no data is coming in…
rtl_test -t
Found 1 device(s):
0: Nooelec, NESDR SMArt v5, SN: 00000001
Using device 0: Generic RTL2832U OEM
Detached kernel driver
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
[R82XX] PLL not locked!
Sampling at 2048000 S/s.
No E4000 tuner found, aborting.
Reattached kernel driver
And the error message is gone.
What made you think it had stopped working before? No planes on the map(s)? Did you check the status online on the FA website?
First of all, I want to thank you for your patience with me. I feel so sorry and bad about it.
On flightaware, everything is green but there is no planes on the map. FR24 is detecting some planes on the map but it’s not detecting as many as I had when I had flightaware alone.
Should I try to uninstall FR24, flightaware and start from scratch? If so, I guess, I will still have some issues and I would still need some help… 
If you’re fine with another decoder and the removal of dump1090-fa, you can use this script which will fix almost all misconfigurations in the book.
https://github.com/wiedehopf/adsb-scripts/wiki/Automatic-installation-for-readsb
Changes in performance might be related to changing the SDR.
Is that the local website or piaware skyware? If by any chance the local ip address changed, it might still load the cached map but no data?
You are running adaptive gain, that might influence the reception. Graphs 1090 could be helpful here, but you’d have to install those separately.
Thank you again but for now, I want to use the official installation for flightaware and FR24.
I checked again and now, both are showing data (planes). Unsure what happened.
However, I am still having the error when running:
rtl_test -t
Found 1 device(s):
0: Nooelec, NESDR SMArt v5, SN: 00000001
Using device 0: Generic RTL2832U OEM
usb_claim_interface error -6
Failed to open rtlsdr device #0.
Both Flightaware and FR24 are working though… but not as I am expecting. I can look at graphs 1090 later on, when this error is gone, possibly…
This just means, that another software is exclusively using the dongle, and rtl_test cannot access it.
It is either dump1090-fa or rtl_test, but not both at the same time.
This will always happen, when you run rtl_test while dump10-fa is active at the same time.
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This makes total sense. This means, I will always get that error message. Gotcha!
So now that flightaware and FR24 are being fed, should I look at why I am not getting great results ?
Not always. But always if you have dump1090 (or any other software) running which blocks the stick for exclusive access to rtl_test.
Would be the same if you board an aircraft and you see that your seat is already occupied. You cannot sit there until the other person gets off the seat.
Same as for the stick. It can be used by one application at the same time, but not two more.
2 Likes
Hey guys,
I just wanted to give you an update. After reading reviews and also after doing everything that was asked here, I decided to install adsb, to test it out. It appears that I couldn’t see very far with that either and I decided to return my dongle. Now, I am waiting for my flightaware dongle, the blue one, with the filter as it appears to be much better but also dedicated to that purpose.
Once received and installed, I’ll let you know how it works.
I want to thank you all of you who helped me with my issue which was probably a hardware issue 
1 Like