Low RSSI uplinks

LPWAN Industrial Gateways / Concentrators WisGate Connect RAK7391
1

Hi,

I’m having very poor RSSI at few meters from my gateway (RAK7931). I’m getting around -60 at ~1m from the gateway.

Could it be due to my global_config.json?

{
    "SX130x_conf": {
        "com_type": "USB",
        "com_path": "/dev/ttyACM0",
        "lorawan_public": true,
        "clksrc": 0,
        "antenna_gain": 0,
        "full_duplex": false,

        "radio_0": {
            "enable": true,
            "type": "SX1250",
            "freq": 902700000,
            "rssi_offset": -215.4,
            "tx_enable": true,
            "tx_freq_min": 923000000,
            "tx_freq_max": 928000000
        },
        "radio_1": {
            "enable": true,
            "type": "SX1250",
            "freq": 903300000,
            "rssi_offset": -215.4,
            "tx_enable": false
        },

        "chan_multiSF_0": {"enable": true, "radio": 0, "if": -400000},
        "chan_multiSF_1": {"enable": true, "radio": 0, "if": -200000},
        "chan_multiSF_2": {"enable": true, "radio": 0, "if": 0},
        "chan_multiSF_3": {"enable": true, "radio": 0, "if": 200000},
        "chan_multiSF_4": {"enable": true, "radio": 1, "if": -200000},
        "chan_multiSF_5": {"enable": true, "radio": 1, "if": 0},
        "chan_multiSF_6": {"enable": true, "radio": 1, "if": 200000},
        "chan_multiSF_7": {"enable": true, "radio": 1, "if": 400000},

        "chan_Lora_std": {
            "enable": true,
            "radio": 0,
            "if": 300000,
            "bandwidth": 500000,
            "spread_factor": 8,
            "implicit_hdr": false,
            "implicit_payload_length": 17,
            "implicit_crc_en": false,
            "implicit_coderate": 1
        },

        "chan_FSK": {
            "enable": false,
            "radio": 1,
            "if": 300000,
            "bandwidth": 125000,
            "datarate": 50000
        }
    },

    "gateway_conf": {
        "gateway_ID": "0016C001F136F95E",

        "server_address": "127.0.0.1",
        "serv_port_up": 1700,
        "serv_port_down": 1700,

        "keepalive_interval": 10,
        "stat_interval": 30,
        "push_timeout_ms": 100,

        "forward_crc_valid": true,
        "forward_crc_error": false,
        "forward_crc_disabled": false,

        "gps_tty_path": "",

        "ref_latitude": 0,
        "ref_longitude": 0,
        "ref_altitude": 0,

        "beacon_period": 0,
        "beacon_freq_hz": 923300000,
        "beacon_freq_nb": 8,
        "beacon_freq_step": 600000,
        "beacon_datarate": 12,
        "beacon_bw_hz": 500000,
        "beacon_power": 27
    },

    "debug_conf": {
        "ref_payload":[
            {"id": "0xCAFE1234"},
            {"id": "0xCAFE2345"}
        ],
        "log_file": "loragw_hal.log"
    },

    "chan_multiSF_All": {
        "spreading_factor_enable": [5,6,7,8,9,10,11,12]
    }
}

I’m can’t confirm that no downlink were sent without the antenna. Do you have an idea of a test I could try to test if it’s an hardware issue or not?

Thanks,

Alex

2

Hello Alexandre,
RSSI of -60 is normal if you are close. The SNR is an important value here to suspect issues.
Can you share your SNR values?

3

Hi,

Thanks for your answer.
I didn’t mention it, but I discovered the problem. The LoRa N-Type connector was not working. The assembly of it in the factory was not done correctly.

Alexandre

4

Never do this, you need a few meters and preferably brick wall between your nodes and gateway, you have a good chance of damaging the gateway or device receivers. LoRa - (Long range radio access)

5

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