RAK5146 get lora trame only

We are working with the RAK5146 USB EU868, mounted on Wisgate connect base kit SKU 815065, with RAK raspbery os.
We want to retrieve lora frames directly, not lorawan frames.
We use loragw_hal: sx1302_hal/libloragw at master · Lora-net/sx1302_hal · GitHub
But without success, we don’t see any reception.
The node is equipped with an SX1262, SF7, BW 125kHz, it only transmits lora frames, with a 16-bit preamble.
We use the meshtastic framework.
Please, do you have any suggestions? An example command line?