I’m having a bit of an issue with a custom MSP430 + SX1276 board.
At first I had some issues with getting join requests through to a TTIG gateway (in EU868 mode). It wouldn’t receive them until LMIC had gotten around to lowering the SF to around 10 or 11. I tried the same version (latest) of the library on a TTGO OLED ESP32 board, which worked fine (at SF7), so I took a look at the radio spectrum and realized my board was sending at an approx 50kHz lower frequency than the TTGO board.
lorabase_eu868.h and increasing the frequencies by 50k, the device started joining reliably every time.
What might be the cause of this issue, and is there a “proper” way of fixing it in the firmware? The board is using a 32MHz ±10ppm crystal.