LoRa-E5 fail to communicate with TTN in low temperature condition

Hi,

I’m using a LoRa-E5 module to send datas on TTN. The LoRa-E5 is factory programmed, and I use it with AT commands, send by a microcontroller.

I have a TTN gateway, and I achieve to send datas to TTN since some months, without any trouble.

Currently, there are negative temperatures at night, and I don’t receive datas on TTN during nights.

I can reproduce this comportment putting my device in a freezer.
I logged temperatures of the freezer and the temperature returned by the LoRa module. Below -6°C (around 5°C in the module), the LoRa-E5 don’t achieve to send datas.

This is my LoRa-E5 configuration:

AT+LW=VER,103
AT+MODE=LWOTAA
AT+DR=US915
AT+CH=NUM,8-15
AT+JOIN

I send messages with the command AT+CMSGHEX.

TTN answers:

I tried to:

  • Activate or not the ADR
  • Change the antenna
  • Disconnect and connect again the LoRa-E5 to TTN
  • Reset the module (software reset and power-cycle)
    But there is no change.

When I reset the module, the JOIN fail. When the module go back to ambient temperature, it can communicate.

I also check the power supply, and there is no trouble.

Does anyone use a LoRa-E5 with negative temperature without any trouble?
Is there any other configuration to allow me to communicate with these temperatures?

Thanks,
Anthony