Hi brocaar , Recently I encountered a problem with downlink. I am using the EU868 band. I set my downlink frequency to 869525000 and data rate 0, but when I send a downlink it will use the last uplink frequency. And I did not receive any downlink.
That’s the way LoRaWAN works in the specification published by the LoRa Alliance which defines what LoRaWAN is.
The first downlink opportunity is in the RX1 window, using the same frequency and spreading factor as the node chose for the uplink.
Only the second downlink opportunity in the RX2 window has singular settings which you can customize.
Under the LoRaWAN spec, the network server gets exclusive right to chose either window (or with some backhaul protocols it can delegate the choice to the gateway)