RAK831 USA 915 MHz not working probably

Gateways Raspberry Pi Gateways
1

Hello,

Ate the moment i’m trying to get the RAK831 working for in Brasil, in Brasil we use the same frequencies as in the USA. I used the following tutorial:
https://www.thethingsnetwork.org/labs/story/rak831-lora-gateway-from-package-to-online
I have the same kit as in the tutorial, but for 915 MHz.

I did read the following post: The hard RAK831 cafe part 1

But without any luck, in most cases I don’t receive nothing. Sometime i get some LoRa packets, but with a really bad RSSI on a really close distance.

Does somebody have the same problem?

I’m using the following global_conf.json

{
"SX1301_conf": {
	"lorawan_public": true,
	"clksrc": 1,
	"clksrc_desc": "radio_1 provides clock to concentrator",
	"antenna_gain": 0,
	"antenna_gain_desc": "antenna gain, in dBi",
	"radio_0": {
		"enable": true,
		"type": "SX1257",
		"freq": 904300000,
		"rssi_offset": -166.0,
		"tx_enable": true,
		"tx_freq_min": 923000000,
		"tx_freq_max": 928000000
	},
	"radio_1": {
		"enable": true,
		"type": "SX1257",
		"freq": 905000000,
		"rssi_offset": -166.0,
		"tx_enable": false
	},
	"chan_multiSF_0": {
		"desc": "Lora MAC, 125kHz, all SF, 903.9 MHz",
		"enable": true,
		"radio": 0,
		"if": -400000
	},
	"chan_multiSF_1": {
		"desc": "Lora MAC, 125kHz, all SF, 904.1 MHz",
		"enable": true,
		"radio": 0,
		"if": -200000
	},
	"chan_multiSF_2": {
		"desc": "Lora MAC, 125kHz, all SF, 904.3 MHz",
		"enable": true,
		"radio": 0,
		"if": 0
	},
	"chan_multiSF_3": {
		"desc": "Lora MAC, 125kHz, all SF, 904.5 MHz",
		"enable": true,
		"radio": 0,
		"if": 200000
	},
	"chan_multiSF_4": {
		"desc": "Lora MAC, 125kHz, all SF, 904.7 MHz",
		"enable": true,
		"radio": 1,
		"if": -300000
	},
	"chan_multiSF_5": {
		"desc": "Lora MAC, 125kHz, all SF, 904.9 MHz",
		"enable": true,
		"radio": 1,
		"if": -100000
	},
	"chan_multiSF_6": {
		"desc": "Lora MAC, 125kHz, all SF, 905.1 MHz",
		"enable": true,
		"radio": 1,
		"if": 100000
	},
	"chan_multiSF_7": {
		"desc": "Lora MAC, 125kHz, all SF, 905.3 MHz",
		"enable": true,
		"radio": 1,
		"if": 300000
	},
	"chan_Lora_std": {
		"desc": "Lora MAC, 500kHz, SF8, 904.6 MHz",
		"enable": true,
		"radio": 0,
		"if": 300000,
		"bandwidth": 500000,
		"spread_factor": 8
	},
	"chan_FSK": {
		"desc": "FSK disabled",
		"enable": false
	},
	"tx_lut_0": {
		"desc": "TX gain table, index 0",
		"pa_gain": 0,
		"mix_gain": 8,
		"rf_power": -6,
		"dig_gain": 0
	},
	"tx_lut_1": {
		"desc": "TX gain table, index 1",
		"pa_gain": 0,
		"mix_gain": 10,
		"rf_power": -3,
		"dig_gain": 0
	},
	"tx_lut_2": {
		"desc": "TX gain table, index 2",
		"pa_gain": 0,
		"mix_gain": 12,
		"rf_power": 0,
		"dig_gain": 0
	},
	"tx_lut_3": {
		"desc": "TX gain table, index 3",
		"pa_gain": 1,
		"mix_gain": 8,
		"rf_power": 3,
		"dig_gain": 0
	},
	"tx_lut_4": {
		"desc": "TX gain table, index 4",
		"pa_gain": 1,
		"mix_gain": 10,
		"rf_power": 6,
		"dig_gain": 0
	},
	"tx_lut_5": {
		"desc": "TX gain table, index 5",
		"pa_gain": 1,
		"mix_gain": 12,
		"rf_power": 10,
		"dig_gain": 0
	},
	"tx_lut_6": {
		"desc": "TX gain table, index 6",
		"pa_gain": 1,
		"mix_gain": 13,
		"rf_power": 11,
		"dig_gain": 0
	},
	"tx_lut_7": {
		"desc": "TX gain table, index 7",
		"pa_gain": 2,
		"mix_gain": 9,
		"rf_power": 12,
		"dig_gain": 0
	},
	"tx_lut_8": {
		"desc": "TX gain table, index 8",
		"pa_gain": 1,
		"mix_gain": 15,
		"rf_power": 13,
		"dig_gain": 0
	},
	"tx_lut_9": {
		"desc": "TX gain table, index 9",
		"pa_gain": 2,
		"mix_gain": 10,
		"rf_power": 14,
		"dig_gain": 0
	},
	"tx_lut_10": {
		"desc": "TX gain table, index 10",
		"pa_gain": 2,
		"mix_gain": 11,
		"rf_power": 16,
		"dig_gain": 0
	},
	"tx_lut_11": {
		"desc": "TX gain table, index 11",
		"pa_gain": 3,
		"mix_gain": 9,
		"rf_power": 20,
		"dig_gain": 0
	},
	"tx_lut_12": {
		"desc": "TX gain table, index 12",
		"pa_gain": 3,
		"mix_gain": 10,
		"rf_power": 23,
		"dig_gain": 0
	},
	"tx_lut_13": {
		"desc": "TX gain table, index 13",
		"pa_gain": 3,
		"mix_gain": 11,
		"rf_power": 25,
		"dig_gain": 0
	},
	"tx_lut_14": {
		"desc": "TX gain table, index 14",
		"pa_gain": 3,
		"mix_gain": 12,
		"rf_power": 26,
		"dig_gain": 0
	},
	"tx_lut_15": {
		"desc": "TX gain table, index 15",
		"pa_gain": 3,
		"mix_gain": 14,
		"rf_power": 27,
		"dig_gain": 0
	}
},
"gateway_conf": {
	"gateway_ID": "",
	"server_address": "router.us.thethings.network",
	"serv_port_up": 1700,
	"serv_port_down": 1700,
	"servers": [ {
		"server_address": "router.us.thethings.network",
		"serv_port_up": 1700,
		"serv_port_down": 1700,
		"serv_enabled": true
	} ]
}

}

2

What are you using for an antenna?
This evening, standing on the roof of a 13-story building in Boston, USA holding a TTN node I turned on TTN Mapper and was quickly told that I had successfully passed a packet (RSSI -97) to a gateway that I understand to be a Raspberry Pi with RAK831 USA frequency, located indoors about 3000 meters away. Not sure what that device’s antenna is.

3

On the RAK831 i use the antenna that comes with it. On the RN2903 i use also the antenna that got delivered with it. Also tried wire antennas at a 1/4 wavelength, but no different. I have the feeling there is a mismatch in the configuration. If i receive a msg (almost never) on a distance of less than 5 meters, the RSSI is around -120.

4

That funny. With a RFM95, with the following setting “LMIC_selectSubBand(1);” the rak831 is receiving correctly. With the gateway form Microchip I used the following setting “LMIC_selectSubBand(0);” Could it be the RN2903 is configured incorrectly? I will have a look later on.

#elif defined(CFG_us915)
// NA-US channels 0-71 are configured automatically
// but only one group of 8 should (a subband) should be active
// TTN recommends the second sub band, 1 in a zero based count.
// gateway-conf/US-global_conf.json at master · TheThingsNetwork/gateway-conf · GitHub
LMIC_selectSubBand(1);
#endif