Problems to log packets using the concentrator board based on Semtech SX1301


#1

Hi,
I am using a concentrator board based on Semtech SX1301 along with a Raspberry. My goal is to use it as a gateway to receive packet from nodes. These nodes are esp32 boards connected with a SX1276 LoRa radio.
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For while I am just trying to test the communication between one node and the concentrator. So I found a whole library who implements the HAL (Hardware Abstraction Layer) and also has also some utilities like “tx test, packet logger”, these utilities are pre compiled programs to test a transmission or a reception for example.
This is the link for all this: https://github.com/Lora-net/lora_gateway
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When I tried to run util_packet_logger on the concentrator, I ran also a code sending a constant byte in loop on my node.
The result was the followings:

  • The logger file in the concentrator did catched packets and if I turn off the node it stops logging. This is a proof that the GTW is receiving something.

  • The logger file has a topic “payload” that was full of non sense bytes. The Byte I sent was not there. I think it was garbage.

I am just starting with LoRa and it all, does someon could give me a hint about what is happening?
Thanks!


#2

Data sent over LoRaWan is both encoded and encrypted. You’ll need the keys in use by the node (either fixed in ABP or temporary in OTAA) and a knowledge of how the packets are structured and encrypted in order to make sense of them. There’s an online decode you can find with a search and use.

But if you are using LoRaServer, you can also view this information in the web interface.

Also note that if your node is configured for OTAA and you don’t have it connected to a functioning server, what you are seeing would not be your application traffic at all, but rather unsatisfied join requests. In some node firmwares, attempting to send application data while still unjoined may trigger another join request, so there could be the appearance of time correlation with your application.