LoRa 2.4GHz - backend/semtechudp:packets: invalid CodR: OFF

Hi,

Hello,

I am working on a project using LoRa 2.4GHz and need some assistance with configuration and performance.

Here are the details of my setup:

Development Environment: SES 8.18, nRF5 SDK Version 17.1, nRF52832.
Transceiver: E28-2G4M12S (SX1280).
Gateway: MikroTik wAP LR2 kit.
chirpstack --version 4.9.0
chirpstack-gateway-bridge version 4.0.11

I can send uplinks to the gateway, but I get the following error in the ChirpStack Gateway Bridge logs:

´nov 21 10:32:51 santos chirpstack-gateway-bridge[35649]: {“addr”:{“IP”:“192.168.88.1”,“Port”:57128,“Zone”:“”},“data_base64”:“AgGpAJNX70hTWDU5eyJyeHBrIjpbeyJjaGFuIjoxLCJjb2RyIjoiT0ZGIiwiZGF0YSI6IiIsImRhdHIiOiJTRjEyQlc4MTIiLCJmb2ZmIjotMTkwNTQ2LCJmcmVxIjoyNDc5LjAwMDAwMCwibHNuciI6LTI0LjAwMDAwMCwibW9kdSI6IkxPUkEiLCJyc3NpIjotMTA0LCJzaXplIjowLCJzdGF0IjoxLCJ0bXN0Ijo0NDUwNjc1NDR9XX0=”,“error”:“get uplink frames error: backend/semtechudp/packets: get uplink frame error: backend/semtechudp:packets: invalid CodR: OFF”,“level”:“error”,“msg”:“backend/semtechudp: could not handle packet”,“time”:“2024-11-21T10:32:51-03:00”}`

My chirpstack-gateway-brigde.toml:

# This configuration provides a Semtech UDP packet-forwarder backend and
# integrates with a MQTT broker. Many options and defaults have been omitted
# for simplicity.
#
# See https://www.chirpstack.io/gateway-bridge/install/config/ for a full
# configuration example and documentation.
[general]
# debug=5, info=4, warning=3, error=2, fatal=1, panic=0
log_level=4

log_json=true

# Gateway backend configuration.
[backend]
# Backend type.
type="semtech_udp"

  # Semtech UDP packet-forwarder backend.
  [backend.semtech_udp]

  # ip:port to bind the UDP listener to
  #
  # Example: 0.0.0.0:1700 to listen on port 1700 for all network interfaces.
  # This is the listener to which the packet-forwarder forwards its data
  # so make sure the 'serv_port_up' and 'serv_port_down' from your
  # packet-forwarder matches this port.
  udp_bind = "192.168.88.254:1700"
  
  # Skip the CRC status-check of received packets
  #
  # This is only has effect when the packet-forwarder is configured to forward
  # LoRa frames with CRC errors.
  skip_crc_check = false



# Integration configuration.
[integration]
# Payload marshaler.
#
# This defines how the MQTT payloads are encoded. Valid options are:
# * protobuf:  Protobuf encoding
# * json:      JSON encoding (easier for debugging, but less compact than 'protobuf')
marshaler="json"

  # MQTT integration configuration.
  [integration.mqtt]
  # Event topic template.
  event_topic_template="ism2400/gateway/{{ .GatewayID }}/event/{{ .EventType }}"

  # Command topic template.
  command_topic_template="ism2400/gateway/{{ .GatewayID }}/command/#"

  # MQTT authentication.
  [integration.mqtt.auth]
  # Type defines the MQTT authentication type to use.
  #
  # Set this to the name of one of the sections below.
  type="generic"

    # Generic MQTT authentication.
    [integration.mqtt.auth.generic]
    # MQTT server (e.g. scheme://host:port where scheme is tcp, ssl or ws)
    server="tcp://192.168.88.254:1883"

    # Connect with the given username (optional)
    username=""

    # Connect with the given password (optional)
    password=""

I got the base64 code:

AgHAAJNX70hTWDU5eyJyeHBrIjpbeyJjaGFuIjoxLCJjb2RyIjoiT0ZGIiwiZGF0YSI6Ijl0SkJSeFpaWGlOR25yUklSWFhBQ2gwPSIsImRhdHIiOiJTRjEyQlc4MTIiLCJmb2ZmIjotMzc4OTUsImZyZXEiOjI0NzkuMDAwMDAwLCJsc25yIjo2LjAwMDAwMCwibW9kdSI6IkxPUkEiLCJyc3NpIjotNTMsInNpemUiOjE3LCJzdGF0IjoxLCJ0bXN0IjoyMDM1NTUwMzE4fV19

�WHSX59{“rxpk”:[{“chan”:1,“codr”:“OFF”,“data”:“”,“datr”:“SF12BW812”,“foff”:-190546,“freq”:2479.000000,“lsnr”:-24.000000,“modu”:“LORA”,“rssi”:-104,“size”:0,“stat”:1,“tmst”:445067544}]}

You are seeing the error because the codr value is not expected. For 2.4 GHz, this is the expected coding rate: chirpstack/lrwn/src/region/ism2400.rs at master · chirpstack/chirpstack · GitHub.