Hi everybody, I am new to the LoRa technology and try to setup a SX1272 to receive a LoRa packet send with another SX1272. The trancseivers are attached to seperate microcontrollers. From the spectrum analyser I can see that the transmittet packet is well and also at the RFI pin of the other SX1272 I have still a good signal quality. But I do something wrong within the configuration of the registers and so when the SX1272 set to continious receive it does not allways detect the packet. It is rather rare even that it detects the packet and then the packet RSSI is -37,5dBm even with the spread spectrum around the center frequency having -3dBm at the RFI pin. Most of the time I do not detect the packet and sometimes there is a payloadCRC error, seldom the packet is received. I set the preamble length on both devices the same, also the bw, the CodingRate and the SpreadingFactor.
What register I might miss?
I read that there is an option to set FSK registers during LoRA mode, but I only found the RegRxBw which looks intersting to me. But even with the FIR filter set to 62.5kHz single side bandwith I don’t receive the packets.
All ideas are appreciate. Many thanks in advance.
There are several LoRa libraries for Arduino out there and they will have basic TX and RX examples.
So download a library and follow the code to see which registers the example writes to.
Hi stuart, thanks for the hint.
From the Arduino example i see that the RegInvertIQ register uses a different value when the default value. Using that also on my application and it works. So i did set InvertIQTX to “I and Q signals are inverted” and InvertIQRX to “normal mode”. I have read a bit about IQ signals, but it is not the field of my expertise. So I still don’t understand why, when sending it with inverted IQ and receiving it with the setting no inverted IQ, the communication works but it does.