Hi,
We have a few tousands units, with the RAK3172 modules inside, deployed around the world. We are now struggling with connectivity issues on some units that seems related to temperature.
The units are supplies with grid power (no batteries) and are combined in a network of around 900 units on a industial indoor area. We have a custom modified variant of the lora stack to adapt to our application.
The issue we see in the field and also have been able to recreate in an office envirnoment, is that if we increase the ambient temperature around the RAK chipset (to around 50 degree celcius), the communication to the unit from the gateway still works, but communication from the unit to the gateway stops working. We suspect that also the communication to the unit also breaks but at a higher ambient temperature.
All other electronics on the board has been eliminated and the RAK chip has been powered by a lab supply directly with 3.3V. Our suspicions are aimed for the XTAL suppling the frequency to the radio part. Any ideas from you guys?