⚡ Semtech LR2021 LoRa chip becomes SDR

The Semtech LR2021 LoRa transceiver now supports software-defined radio operation from 100 MHz to 2.74 GHz via the open-source LR2021-SDR project. Developed by Samuel Reynolds, this firmware leverages an undocumented ROM command to expose raw 16-bit I/Q samples directly from the chip. This approach mirrors recent projects that repurpose standard wireless hardware for wideband signal reception without external dongles.

The implementation allows software to decode P25 Phase 1 digital voice, POCSAG pager messages, and analog FM signals. The receive frequency range extends beyond the datasheet specifications of 150–960 MHz and 1.5–2.5 GHz. Experimental testing confirmed functionality across the broader 100 MHz to 2.74 GHz spectrum, offering significant flexibility for radio enthusiasts and developers.

Compatibility is strictly limited to the Semtech LR2021 running ROM version 1.24. The project explicitly notes that the SX1262 variant is not compatible for raw I/Q access. This distinction is critical for users attempting to adapt existing LoRa modules, as hardware differences prevent universal application of the firmware. The project follows similar initiatives like the w1700k-sdr, which converted a Wi-Fi 7 router into a receiver.