The other day i noticed that for some odd reason, data has gone from ~2000 messages sec/ ~250 aircraft seen and for some unknown reason it plummeted to 300-600 messages per second and less than 100 aircraft. Rebooting seemed to fix the issue but it would come back some random amount of time later. This is a Pi 4, running 32 bit Bookworm on POE power (POE Hat). Flightaware package is added on along with other feeder packages. Has anyone ever seen anything like this? any suggestions? Thanks!
There are many reasons performance drops off.
Loose antenna connector, water ingress into the coax, damaged antenna, failing SD card and the very common ‘soft power supply’.
Checking the connections (at least at the bottom end) is easy. Try a different PSU is also easy (if you can get to the Pi).
A cheap ($1 ~ $2) USB voltmeter plugged into a spare USB port is very informative.
Thanks for your suggestions. The antenna is definitely not waterlogged, it was just checked last week and is wrapped in weatherproof 3m. Antenna has an SWR of about 1.3 so I’m happy with that. I tend to think that it’s power related as well. I was using the POE hat but I removed it last night and plugged it in instead. So far it has been running excellent and showing ~300 aircraft and ~2300 messages/sec. I’m going to get a new SD as well as a USB voltage tester and see what I can find out.
1 Like
I am still incredibly perplexed by this. It does not appear to be a power or SD card issue. It dropped again today and only seemed to recover when the amplifier was removed so it’s almost certainly the issue. Still going to do some more testing before deciding to buy another amp. I’ve attached a screenshot of graphs1090 where you can see the sudden drop in message and aircraft.
ReplyDiscard
Is there something changed in your surroundings ? New mobile phone transmission station maybe ? Did you try a filter before the amplifier ? What kind of amplifier are you using? It could be something is overloading the amplifier and that will result in the symptoms you are seeing.
So the setup is flightaware 1090 filter going to an Uptronics filter amp. Amp is feeding the flightaware pro stick plus. Running on a raspberry pi 4 that is POE powered. The amp is USB C powered. There is also a GPS dongle that feeds data to the ads-s programs. No new interference that i know of. It just randomly loses like half of the aircraft/messages randomly some time during the day. Rebooting does nothing nor does trying a different dongle. Only works when I remove the amp. I even used a different pi thinking something could be wrong with the one feeding. I’m going to try a different power supply for the amp next.
Is the amplifier maybe overheating ? Maybe you can check in graphs1090 ? Just trying to think what the issue might be.
I attached a screenshot of graphs1090 in my original post and you can see where it drastically changes. Amplifier is barely warm to the point it’s not even noticeable really. The power LED is on when I power it. At this point I’m going to let it run for several more hours and sometime today change it’s power supply brick, and see if that’s a possibility. Just want to make sure it’s bad before spending $70 on a new one.
1 Like
The screenshot doesn’t display the temperature.I can see the change in traffic indeed but that was not the question.
I can imagine you want to be sure, it there no warranty on the item anymore?
Fairly certain there is no warranty left as i’ve had it up and running for about 3 years. If you were asking about the pi temperature, it runs around the 52c area and doesn’t change much.
FA prostick has an LNA … it’s not much worse than the uputronics.
Just take the uputronics out of the equation.
You should also check if you can get away without the filter in front or if it is beneficial.
3 Likes
After testing over the last few days, it appears that the uptronics will work just fine for several hours but ultimately at some point it fails. It still “works” but only shows ~75-100 aircraft and 6-700 messages per second. As soon as it’s removed it jumps back to the usual ~250+ aircraft and 1800-2000 messages per second. I have a suspicion that the lightning/power surge got to it. Thank you all for your input!
1 Like
Just saw your message and I had a pi4 system similar to yours. Reduced performance periodically and finally solved the problem when I removed the GPS dongle. Required location to be manually set and time vi net somewhere. It worked for me, and might be a factor. Experiment and see if this makes a difference over a week or so. Good luck!
I may try that. I put a new amp on it but discovered that wasn’t the issue prior to even installing it. I’ve tried almost everything i can think of, it’s like it just loses roughly half of the aircraft and message rate after 48-72 hours. In order to fix it, i have to shutdown and remove the power (poe). Right now it’s been going on 48 hours and the only difference is I removed the POE hat and powered it via usb-c thinking the hat may be bad. Guess I’ll see and that GPS will probably be next on the list of things to try.
ADS-B is a heavy user of the USB bandwidth. My GPS dongle was messing with the bandwidth evidently and I suspect the software downgraded the connection to try to “fix” the problem. Very annoying. Removing the GPS dongle cleared the problem.
I also did a test of USB2 vs USB3 connectors. USB2 consistently worked more reliably and collected more positions/flights. Not sure about why specifically, except in reading about Pi4’s usb interfaces, it did mention internally these were treated differently. Both flightaware pro and Airspy dongles are configured as USB2, so I only use those for the dongles. I do use the USB3 connector for a Bias-T device to power the inline amplifier up at the antenna. Antenna > amp > BiasT > AirspyR2. You could power the amp using the R2 or mini BiasT configuration option, but I suspect the voltage is a bit lower and my R2 did get hotter. Hotter means more noise, so that is why I went with a separate BiasT board and used a old USB cable with the end removed and used the red & black wires for the power to the board. Hope that makes sense. Much if this hobby is about experimenting to see if we can make things work better.
If you really want too have the GPS dongle connected, perhaps one of the Pi5 systems with the separate USB interfaces could work better, though at the penalty of higher power consumption. Have fun with experimenting.
I think you may exactly right. It will work perfectly for 48-72 hours and then suddenly it will lose about half the aircraft and the message rate will plummet. A shutdown and restart usually does nothing to fix it. I’ve found that unplugging the receiver and GPS and reconnecting the receiver will usually work after restarting the dump1090 and piaware services. I will then reconnect the GPS and all is well…for a little while. As of right now I keep a close eye on it and am experimenting with things. Thanks for all your help!
Matt
The most common cause of sudden performance drop is the PSU going soft.
Try an alternative power supply and see if it helps
Just curious to know why people use GPS dongle with a stationary receiver when entering correct coordinates (accurate to 4 or 5 places of decimal) in “My-ADSB” page once is enough? Does not GPS dongle put some extra load on PSU?
I have removed the POE hat and used a POE splitter that has an rj45 and type C plug for power. Makes no difference at all. Even used the official Pi type C psu and same thing, no difference.
GPS provides a very accurate time signal. It might not be necessary exactly as you can get close with NTP, but it’s nice to have an independent time reference available.
1 Like