How to diagnose random connection loss?

FlightAware ADS-B Flight Tracking
1

Hi all,

I hope someone can help me with the following; I have a basic RPi 3 set up with a Flightaware Pro stick which until a few weeks ago worked flawlessly. In the last three weeks the RPi lost connection a few times without apparent reason. I’m wondering what the best way is to diagnose the actual the problem?

I actually did not touch the set up (at all) and a simple reboot fixes the connection, but I’d like to understand what’s happening. Unfortunately I’m neither an expert the electronics nor the RPi, but perhaps someone can give me some pointers i.e. how to best review the log, do error checking etc.

Thanks in advance!

KR, FS

2

Can you still reach the RPi when the connection loss happens, or is all connectivity lost?
Does the local SkyView still work?

You’ll need command line access, do you have that for example via SSH?
(For Beginners - How-to SSH to RPi - Setup Putty in Windows user:pi password:flightaware)

These are the two logs that are most interesting:

journalctl -eu piaware | grep -v 'reported location\|--lat\|feeder ID'
journalctl -eu dump1090-fa

The logs are in RAM by default so a reboot will delete them.
You can make the survive a reboot by editing

sudo nano /etc/systemd/journald.conf

Storage needs the # removed and set to persistent.
You can also limit the maximum amount of space the logs will take up but it’s not that important.

[Journal]
Storage=persistent
#Compress=yes
#Seal=yes
#SplitMode=uid
#SyncIntervalSec=15m
#RateLimitIntervalSec=30s
#RateLimitBurst=1000
SystemMaxUse=30M

Do a reboot for these log changes to take effect.

3

This comes up quite often - the RPi is working, but not decoding. A reboot fixes the problem for a while, but then it fails again - sound familiar?
If so, bin your PSU and find something better. Phone chargers are notorious for short lives when used continuously.

4

There are power supplies specially for the Raspberry Pi which supply 5.2 V (Official Raspberry power supply and Canakit power supply for example)
If you can buy one of those.

5

Thanks … learned something here and will try this…

Best regards!

6

Thank you on the tip on the PSU, will check it’s power output.

Best regards!

7

@wiedehopf, thanks again!

Checking the journal with the ‘journalctl -eu dump1090-fa’ command reveals the following error message:

Apr 16 20:14:01 2019 UTC Caught SIGTERM, shutting down…
Apr 16 20:14:01 FlightAWARE systemd[1]: Stopping dump1090 ADS-B receiver (FlightAware customization)…

Looking for the terms in the rest of the forum reveal that it’s generally preceded by some kind of warning (e.g. 'no data received) but that’s not the case. I guess that does not conclusively rules out hardware (e.g. USB or PSU ) but any other thoughts on this?

Thanks in advance!

8

It’s probably being restarted by piaware, you should check that log as well.
journalctl -eu piaware
Or you can just check the complete journal.
journalctl -e

If piaware tries to restart dump1090-fa it’s almost always because of the PSU issue.

Is your dongle connected directly to the RPi? USB cables often have a voltage drop.

You can also connect it to the RPi via a powered USB hub, that way the dongle gets enough power.