RAK811 SF6 Problems

RAK811 in P2P with SF6 not working correctly.
CR1, BW125KHz, preamble 8
Semtech tool indicates on air time of 64ms. I’m measuring 10ms based on current consumption and UART messages.
It seems that radio inside RAK811 is not programmed correctly in SF6
Firmware V2
We are not able to transmit any data.

Thank you

Hello @frank_r
Are you using a custom firmware? The default AT command firmware does not support SF6. Valid SF are from 7 to 12.

SF6 needs a special handling according to the SX1272 datasheet

Spreading Factor 6
SF = 6 Is a special use case for the highest data rate transmission possible with the LoRa modem. To this end several settings must be activated in the SX1272/73 registers when it is in use. These settings are only valid for SF6 and should be set back to their default values for other spreading factors:

Set SpreadingFactor = 6 in RegModemConfig2
The header must be set to Implicit mode.
Set the bit field DetectionOptimize of register RegLoRaDetectOptimize to value “0b101”.
Write 0x0C in the register RegDetectionThreshold.

I will check with the R&D guys, but I am quite sure they did not implement that.

There is as well a discussion here RAK811 unable to set SF6

Hi begee!
No we are not using special firmware. NOWHERE in RAK documentation does it say SF6 is any different from the other SF. Indeed all RAK documentation indicates that SF6 is fully supported in RAK811. Thus you’re saying RAK is very misleading. Yes I’m aware now, from another post SF6 is not supported in RAK811. This is VERY VERY disappointing and indicates that RAK NEEDS to seriously improve its documentation. And stop giving misleading information.

Hi @frank_r ,

That is sad to hear. I handle the RAK811 documenation RAK811 WisDuo LPWAN Module | RAKwireless Documentation Center

Can you share me the part of the documentation that is confusing so we can improve it.