FlightAware Discussions

MLAT Issues: Clock Unstable


mlat-client(25076): Server status: clock unstable

Is the error I am getting read into other’s issues but I plugged my Pro Stick Plus into the USB directly on the RaspberryPi2 any way to fix this issue?

Been troubleshooting today so I’ve had more data then I ever have. Still think it is unstable though.


Could be the USB being unstable due to the stick not getting enough voltage.
(Try a different USB port, better power supply)

You have probably checked on your status page if the elevation above ground is correctly set and the gps coordinates are correct?

Apart from that i don’t know.

But your stats also show that your receiver has received some mlat results so it’s somewhat working i guess?


Yeah I was playing with it today to see if that might be it we will see if it holds up if you look at my history it’s slim to none.


Also, back down again now.


So did you try another power supply / different usb port?

Also you can run rtl_test to see if you are dropping samples.

sudo service dump1090-fa stop
rtl_test -s 2400000

On startup a few lost samples should be no problem but over the next 10 minutes there should be no errors displayed.

Also kernel 4.9 was apparently having problems with USB on the Pi2
Not sure which image you are running, maybe just try a current one or do a

sudo rpi-update

Note that this can cause issues too and you should be willing to reimage if necessary. (hopefully not though)