Lora Communication between V2 and V3 boards

#1

Because at my order time there was no V2 board available I ordered V3 boards for my sensor network. I can not make the intercommunication between the two boards (V2 and V3). With v3 I adapted my software from the old Lora library to the new RadioLib.
Parameters for the old Lora V2:
Heltec.begin(true /DisplayEnable Enable/, true /LoRa Enable/, true /Serial Enable/, true /LoRa use PABOOST/, 868 /LoRa RF working band/);
for V3:
Radio.SetTxConfig( MODEM_LORA, TX_OUTPUT_POWER, 0, LORA_BANDWIDTH,
´
LORA_SPREADING_FACTOR, LORA_CODINGRATE,

                             LORA_PREAMBLE_LENGTH, LORA_FIX_LENGTH_PAYLOAD_ON,

                             LORA_CRC, 0, 0, LORA_IQ_INVERSION_ON, 3000 );

Radio.SetRxConfig( MODEM_LORA, LORA_BANDWIDTH, LORA_SPREADING_FACTOR,

                             LORA_CODINGRATE, 0, LORA_PREAMBLE_LENGTH,

                             LORA_SYMBOL_TIMEOUT, LORA_FIX_LENGTH_PAYLOAD_ON,

                             0, LORA_CRC, 0, 0, LORA_IQ_INVERSION_ON, true );

with:
#define LORA_BANDWIDTH 0 // [0: 125 kHz,
#define LORA_SPREADING_FACTOR 10 // [SF7…SF12]
#define LORA_CODINGRATE 1 // [1: 4/5,
#define LORA_PREAMBLE_LENGTH 8 // 8 // Same for Tx and Rx
#define LORA_SYMBOL_TIMEOUT 0 // Symbols
#define LORA_FIX_LENGTH_PAYLOAD_ON false
#define LORA_IQ_INVERSION_ON false
#define LORA_CRC true
#define LORA_SYNC_WORD 0x34

Is there any hope for a communication or should I buy the v2 board again?
Why does the Lora V3 chip has a 16-Bit Sync word but the Api provides only a 8 bit parameter?
Which parameter for sync word is correct for function Radio.SetSyncWord(byte sncword); to have communication with V2 with sync word 0x34?
Thank you!

#2

The discussion here might help in working out compatible parameters for V2 and V3 boards.

#3

Thank you for your help. In the end I had all your parameters. Sometimes (maybe 1 from 10 messages) It is shortly working. I spent another day in tries today and I think I will give up now. I developed a own Message/Acknowledge communication system with a central device from makerfabs also with SX1276. With v2 everything was working good but with v3 I can’t make it work. Sometimes I receive messages but I never get an acknowledge from the partner device. But I receive sometimes the periodical status from the partner. So I think it is something with the Sync Word (in my case 0x34). I don’t think that there is a big issue in my software.