Hello guys.
Wanna share one experience with Xbee Pro 868 if you have same problem.
I have clone of UNO with 3.3 V pin output, GPS ultimate shield and Xbee PRO 868. Just sending every 2 sec GPS position over Xbee. After a while (usually in one hour), Xbee stop to sending data and freeze. Arduino is working fine as I still see output on Serial port. On receiving Xbee (connected to USB over Sparkfun) I see RSSI LED goes off.
Reset of Arduino wont help (Xbee is then not found-not comunicating), I have to unplug ang plug power, then it start to sending again and RSSI turns on.
If anybody have some idea what can cause this, I would be greatfull.
Xbee settings: Sending over broadcast - 4 retries, Command mode time out 1s, power on 25mW now, all other registers on default values.