LR2021 Supported BW (<31.25 kHz)?

[henla464]

Does anyone know, or can test if BW 10.4 kHz works on LR2021 in Lora mode (440 Mhz)?

I have read the datasheet and in one table it says:
BWLORA1 - LoRa For frequency range 434MHz - 2500MHz: 7.825-1000 MHz

But then when I look in the table for the BW parameter it lists all below 31.25 kHz as RFU. In other places I read that it should be fully compatible with SX1268 that does support these BW. And there is no mentioning of incompatibility in the 23.7 Compatibility of Generation 1-4 LoRa Radios.

Has anyone tested or can test if BW can be set to 0x0 or 0x1 or 0x8 or 0x9? I don't have the hardware to test this myself.

[jgromes]

Thanks for the hint! I tested it out and looks like the undocumented values (7.8, 10.4, 15.6, 20.8 kHz) do in fact work - the bandwidth on SDR waterfall matches the expectation and SX1262 can receive the packets just fine. See screenshot below for 7.8 kHz. Pushed to master and now LR2021 can handle bandwidths below 31 kHz.

[henla464]

Thank you so much! That is great news!

I assume also the other in the series LR2022 and LR2012 also works the same. I wonder why it is undocumented...