[bombenm]

In the serial monitor, I see: "RF95 init done" and "DS2482-100 not detected" because I haven't connected the Soil Leaf interface yet.

Hi,

If the DS2482-100 chip is installed it should be detected even if Soil Leaf interface isn't connected.

In your Config_Options you have defined the use of both TH_SENSOR0 and TH_SENSOR1 with a sensor STH31 type, that is ok, but both can't be on the same I2C address (0x44)
This info is stated on the code right above the config settings for TH_SENSOR1
 

Code:

// --------------------------------------------------------------------------------------
//   Define type of Temperature / Humidity sensor used as Sensor 1
//   IMPORTANT - If two I2C sensors (SHT31 or SHT2X) are used, each one must have its own I2C address
// --------------------------------------------------------------------------------------

First of all, thank you for your reply.
You’re right that I enabled both sensor 0 and sensor 1 on the same address.
Now I fixed it by putting sensor 1 as not installed.
Nothing has changed.  I will explain my issue.
 
Very often, just feed the board, the red led stays on all the time.
Only after many reset on Arduino Nano board, or, after removing the power to the board, sometime it starts to work and flash the red led.  
This, however, does not last for long.
After a few hours of transmission the red LED lights up again permanently and the transmission stops.
I was thinking about a power issue since the board is powered by a photovoltaic system and the transmission mostly breaks down in the evening, but measuring the battery is ok.
I don’t know where to hit my head anymore.  
Have any of you ever had my problem in the past?
thanks