Based on your report, Thank You. At least it get me confirmation, that indeed SF7 can properly work, esp the RSSI/SNR reading are “real”.
If your condition is per ours, SF7, 250kHz, then:
Absolute Noise floor is -119.8dBm, you get SNR negative at -110dBm, meaning the front-end of your setup (Lora+ others), has a noise figure of 10dB. Not too bad.
we did quite a lot of additional experiment, but as per my pictures above, it all points to the hardware (more on this later). Thus we really hope to hear what can go wrong, as we almost at wit’s end. In terms of software, the whole setup is working perfectly, running one packet every 30ms on SF6 without a glitch. It is a PRBS data, and is AES-128 encrypted, and is cross-checked valid, so it is not just some random received packet. It is not code or other issue, except it is some “unknown” not per documentation.