Hello,
I am using rak3172 module with custom C program with ST library’s. For example I turn on two module with settings:
433 MHz, SF 12, BW 65
First module send 32 bytes per 30 second successfully, but second receives only two interrupts from CAD - “Cad detect” and “Preamble detect”. Other doesnt receive.
If I decrease SF to 10 or below - second device receive package from first successfully.
I am not sure if that the custom C program is based on RUI3 or different. But what I can think of is that if your device are too close to one another, SF11 and SF12 might not be the ideal spreading factors. It will appear that your modules are shouting (just an analogy but of course SF is not about power/amplitude) to one another. Maybe you can try to make them far away and also try if you can successfully send lower size payload.