PiAware With 2 Radios

I built a dual band 1090/978 version of a Stratux. I’m NOT flying way more than I am flying so I figured I’d put PiAware on another SD card and keep it powered on when I’m not using the RPi for Stratux. Before I go flying I just shut it down, swap SD cards and take it with me.

I have 2 SDRs plugged into my RPi for the Stratux application. When I keep them both plugged in with the PiAware SD card my “Feeder Check-In” status stays live and always says “less than a minute”. However, my “Data Feed” status starts to get old. To make the Data Feed status stay fresh, I have to shutdown the RPi and unplug one of the USB dongles. Is there a way that I can make PiAware work with 2 dongles plugged in, but just use 1? Eventually my Stratux will be in a screwed together case with just access to the SD card and I won’t be willing to take it apart every time before and after flying to unplug one of the USB Dongles.

What does /tmp/piaware.out say?
Do you see any USB problems when you run ‘dmesg’?
With 2 dongles I would suspect power problems.

I’ll have to check those two things when I get home this evening.

My Stratux setup runs fine with 2 SDR dongles and USB WiFi dongle off a battery. The PiAware setup is plugged into the wall with a 2A power supply, so that shouldn’t be a problem. I also don’t see the red power light on the RPi falter with 2 dongles.

For reference I’m using this RPi kit and the NooElec Nano SDRs.

The way that power problems tend to manifest first is the dongles randomly resetting or hanging; the USB bus seems to be the first thing to drop out. dump1090/librtlsdr is not very tolerant of this, so everything can just grind to a halt. piaware will usually try to restart dump1090 if it notices there’s no data being fed, but (a) it takes a while before it does that (an hour? something like that) and (b) it doesn’t always work if something has wedged in dump1090 or the USB subsystem. This should show up in the logs, anyway.

If you run the Pi with piaware off battery, does it have the same problem? I really would be suspicious of that power supply; supplies designed for phone charging don’t necessarily actually give you 5V/2A, the voltage can drop right off when you start drawing any notable current, which is fine for battery charging but not so great for a Pi.

The USB power can be problematic on some Pis. I had one Pi2 that will not even run with a single dongle. It would crash sporadically for no apparent reason. Put the dongle on a powered hub, and everything smoothed out. I would try putting your Double Dongle setup on a powered USB hub to see if you have better results with stability.


I shutdown the RPi and plugged in both dongles directly to the USB ports on the RPi and restarted. Everything seems to be working. The Data Feed and Feeder Check-In stats say they are less than 1 minute old.

For reference below are screenshots of the files asked for:

/tmp/piaware.out file
And the dmesg output showing the two dongles.

Looks normal. If/when it fails again, see what they look like at that point.