How to build RF device payload

End Devices (Nodes)
1

I try to build RF device payload inside my own packet-forwarder according:

/*
Name |  Type  | Function
:----:|:------:|--------------------------------------------------------------
time | string | UTC time of pkt RX, us precision, ISO 8601 'compact' format
tmms | number | GPS time of pkt RX, number of milliseconds since 06.Jan.1980
tmst | number | Internal timestamp of "RX finished" event (32b unsigned)
freq | number | RX central frequency in MHz (unsigned float, Hz precision)
chan | number | Concentrator "IF" channel used for RX (unsigned integer)
rfch | number | Concentrator "RF chain" used for RX (unsigned integer)
stat | number | CRC status: 1 = OK, -1 = fail, 0 = no CRC
modu | string | Modulation identifier "LORA" or "FSK"
datr | string | LoRa datarate identifier (eg. SF12BW500)
datr | number | FSK datarate (unsigned, in bits per second)
codr | string | LoRa ECC coding rate identifier
rssi | number | RSSI in dBm (signed integer, 1 dB precision)
lsnr | number | Lora SNR ratio in dB (signed float, 0.1 dB precision)
size | number | RF packet payload size in bytes (unsigned integer)
data | string | Base64 encoded RF packet payload, padded
 */

How should field data look? In my understanding data is the json string converted to bytes, isn’t it? But what’s the format of this json?

2

As far as I know, field ‘data’ contains a string. It’s the raw byte payload (including all LoRaWAN headers) as transferred over the air, encoded using base64. Example: