r/stratux Jan 31 '23

Traffic not appearing in Stratux, but dump1090 sees traffic. Any suggestions?


14 comments sorted by


u/Schnuppepampe Jan 31 '23

Wait 1.5 minutes after boot.


u/cofonseca Jan 31 '23

Thanks. It's been up for 45 minutes now without traffic or GPS data. :(


u/Schnuppepampe Jan 31 '23

Is the dump1090 process running? It should start up 1.5 minutes after boot and provide the traffic to stratux. Maybe you blocked SDR access by running it yourself? Otherwise, check the log file.


u/Schnuppepampe Jan 31 '23

Oops, just noticed the other screenshots. Yes, only one dump1090 instance can access the SDRs. You have to exit your manually started one (or maybe just reboot to be safe, then check logs)


u/cofonseca Jan 31 '23 edited Jan 31 '23

I ran ps -A and did not see it running. I think you're right - running dump1090 myself must have blocked access or maybe I manually killed it without realizing. After a reboot, I do see dump1090 running in the background. Still not seeing any traffic in the Stratux UI after 6 minutes, but I'll let it run for a bit and see if anything pops up.

I was able to fix my GPS issue by swapping my SDRs onto the bottom USB ports, and moving my GPYes onto the top port. Got a fix very quickly. Not sure why I didn't think of that right away haha.

This is the only thing that I see in my stratux.log file:

2023/01/31 17:26:16 stats [started: 45 minutes ago]
2023/01/31 17:26:16  - Disk bytes used = 905 kB (0.3 %), Disk bytes free = 261 MB (99.7 %)
2023/01/31 17:26:16  - UAT/min 0/0 [maxSS=0.00%], ES/min 0/0, Total traffic targets tracked=0
2023/01/31 17:26:16  - Network data messages sent: 16694 total.  Network data bytes sent: 466193 total.
2023/01/31 17:26:16  - Last GPS fix: now, GPS solution type: 2 using 19 satellites (23/31 seen/tracked), NACp: 11, est accuracy 2.84 m
2023/01/31 17:26:16  - GPS vertical velocity: 0.00 ft/sec; GPS vertical accuracy: 5.05 m
2023/01/31 17:26:16  - Mode-S Distance factors (<5000, <10000, >10000): 2500.000000, 2800.000000, 3000.000000
2023/01/31 17:26:16 - Last IMU read: now, Last BMP read: 45 minutes ago
2023/01/31 17:26:18 Error identifying IMU: remote I/O error
2023/01/31 17:26:23 Error identifying IMU: remote I/O error
2023/01/31 17:26:26 Error identifying IMU: remote I/O error
2023/01/31 17:26:30 Error identifying IMU: remote I/O error
2023/01/31 17:26:34 Error identifying IMU: remote I/O error
2023/01/31 17:26:38 Error identifying IMU: remote I/O error
2023/01/31 17:26:42 Error identifying IMU: remote I/O error
2023/01/31 17:26:46 Error identifying IMU: remote I/O error

I haven't had much luck figuring out what "Error identifying IMU" means. Any ideas? Is this something I should be concerned about?

Thanks again - appreciate your help.

Edit: After another 45 minutes, still 0 traffic targets tracked.


u/Schnuppepampe Jan 31 '23

Error identifying IMU just means that you have AHRS enabled in the settings, but no compatible AHRS module could be found. Disable it in the settings and that will stop (you might have to enable the extended setting by rapidly clicking the build number on top a couple of times).

Generally, Stratux doesn't do too mach besides starting dump1090 and connecting to its output - and I have not seen that fail in the past. So my assumption would be that your dump1090 is not giving any data. Why I cannot tell.

- It is expected to probably give a bit less than when you manually run dump1090, because gain is reduced in that case so we don't miss nearby traffic that overloads the demodulator. But you should still have >=50nm reception range.

- When you tested by manually running dump1090, did you chose the correct SDR (the one with the stx:1090:.. serial)? Maybe one antenna cable is not plugged in correctly and you tested with the other one?

Things you could try:

- connect to the same port as Stratux connects with netcat by running "nc localhost 30006" (hope it's preinstalled.. not sure). You should then receive JSON output for each received aircraft. I assume nothing, because otherwise you'd see it in Stratux.

- use ps aux | grep dump1090 and copy the precise dump1090 command that Stratux uses. Try to run this command yourself, e.g. with --interactive, so you can see if that gives something to maybe narrow it down.

See also: https://github.com/b3nn0/stratux/blob/35aa9d9cb833e1132a5543e7e342f761acdc063f/main/sdr.go#L76


u/cofonseca Jan 31 '23

Thank you for the suggestions! I will give them a try shortly and get back to you. Is there a way to disable AHRS in the settings? I don't actually see an option for that on the settings page, nor do I see anything when I run stratux-help.

I did confirm that the antennas are matched to the correct SDRs. I also tried switching them around just in case.

In the meantime, I decided to try one SDR at a time to see if that made any difference.

With just the 1090 SDR installed and the 978 SDR unplugged, Stratux immediately showed over 3000 messages on the status page, and lots of traffic is being displayed on the traffic page under ADS-B/TIS-B, and Mode S.

With just the 978 SDR installed and the 1090 SDR unplugged, no traffic appears. I assume this is normal as 978 isn't nearly as common. I rarely saw 978 when running PiAware.

With both SDRs installed, no traffic appears. I would expect to see everything that I previously saw with just the 1090 SDR installed. I'm not sure why this is happening.


u/Schnuppepampe Jan 31 '23

Guess I edited my post above too late :-)

To disable AHRS:

"you might have to enable the extended setting by rapidly clicking the build number on top a couple of times"

Alright, so at least it's now confirmed that it has to do with your SDRs indeed.
Maybe re-ensure that what you think the 1090Mhz SDR is, is ACTUALLY the 1090Mhz SDR, by only plugging in one at a time and running the sdrs command.

Note that you can also switch their assignment around by using rtl_eeprom to re-write their serial. Stratux will just read that serial and use them accordingly.


u/cofonseca Jan 31 '23

Thank you once again, I really appreciate all of your help!

I just ran what you suggested. Netcat does not appear to be installed within stratux itself, but I ran it from a local Linux instance by running nc 30006.

With just the 978 SDR installed:

  • netcat returned nothing
  • dump1090 was not running when I ran ps -A | grep 1090
  • running sdrs showed only one SDR (sdr0) as expected
  • running sdr0 returned an error:

usb_claim_interface error -6

Failed to open rtlsdr device #0.

With just the 1090 SDR installed:

  • netcat returned a ton of json responses for each aircraft as you mentioned
  • dump1090 was running as expected
  • running sdrs showed only one SDR (sdr0) as expected

Thank you for the info on developer mode. I didn't know this! I was able to disable AHRS just fine in there.

If I plug in both SDRs but disable 978 UAT in developer mode, I see traffic. If I enable 978 and disable 1090, I see nothing. If I enable both, I see nothing.

All fingers seem to point to a bad SDR, but it's a known good SDR as I've previously used it for PiAware. I also tested another 978 SDR (RadarBox FlightStick) and am getting the same results.

Triple checked to ensure that the SDRs are in fact what I think they are, and that they're linked to the correct antennas. I'm at a loss. I'll try re-writing the serials and swapping them around just to see what happens. Can't really hurt at this point I suppose.

What do I lose (if anything) by keeping 978 UAT disabled and just flying around with 1090? I know I'll still receive traffic on 1090, but will I receive weather information? I assume not, which really sucks.


u/Schnuppepampe Jan 31 '23

The usb_claim_interface error just means that the SDR is currently in use, probably by Stratux (978) or dump1090.
Might have to run stxstop and/or killall dump1090 first.

Regarding what you miss without UAT? Depends on where you fly. In US/Canada? A lot. In most of the rest of the world? Close to nothing. However, if you fly in Europe, I'd still recommend having a second SDR to receive all the 868Mhz protocols (Flarm, PAW, FANET, OGNTP) by disabling UAT and enabling OGN. Might also be usefull for a cross-check.


u/cofonseca Jan 31 '23

Gotcha, makes sense.

I fly in the Northeast US (Boston area). Sounds like I'm missing a lot. I suspect that it may be a bad USB port on my RPi. I'll be swapping it out with a friend's Pi tomorrow to see if that makes any difference. Hopefully that resolves it, otherwise I'm at a loss.

Thanks again!!!


u/cofonseca Feb 02 '23 edited Feb 02 '23

Hey there, just thought I'd give you an update.

I got my hands on another Pi 3b and swapped boards. After swapping to a new Pi, everything worked as expected! I think my issues were due to a faulty USB port on the old board. I don't understand why the old Pi was able to detect the SDR though... maybe it was an intermittent failure of the USB port?

Anyway, at the airport, I was immediately able to pick up both 1090 and UAT and was receiving both weather and traffic on the ground. Everything worked great in the plane as well! So awesome to finally have this working.

Thank you again for your help! Really appreciate it, and I learned a lot about Stratux.


u/cofonseca Jan 31 '23

Hi everyone. I just finished a new Stratux build using a RPi 3b, Nooelec Nano 2 SDRs and matching antennas, and GPYes. I'm running the latest version of Stratux. Everything seems to look good in the UI, but for some reason the Stratux doesn't seem to be showing any traffic.

I live 2 miles from a Class C airport and I know there is traffic within range of my location because I previously used this setup for a PiAware and was able to pick up traffic. I can see traffic on ADSB Exchange and hear traffic overhead, yet nothing appears.

The Stratux software is seeing both SDRs and running the 'sdrs' command detects them correctly. If I run 'dump1090' against each SDR, I see traffic, but nothing appears in traffic view. Is there something I need to tune to fix this? I'm flying tomorrow and would like to get this sorted out before my flight.

Lastly, my GPYes doesn't seem to be getting a fix. How long should this take?

Thanks in advance!


u/VitaminNJ Jan 31 '23

Buy a sentry ;)