Last week we posted about BirriaSDR, which turns cheap MT7921-based USB 3.0 Wi-Fi dongles into a 2.4 / 5 GHz SDR. Now Daniel has written in about his project Mtk79ICAP, a similar project that uses a forked Linux mt76 driver and a patched MediaTek firmware to stream 14-bit I/Q from the chip’s internal capture engine.

The key difference is that Mtk79ICAP includes a SoapySDR module, so the dongle works directly in GQRX, SDR++, and GNU Radio Companion. It supports 20, 40, and 80 MHz bandwidths on both bands, including 80 MHz on 2.4 GHz, and Wi-Fi monitor mode can keep running in parallel while I/Q is streamed.

The project is still experimental and Linux-only, with uncalibrated levels and some variability at 80 MHz on 2.4 GHz. Still, with multiple teams now working on these dongles, the MT7921 is quickly maturing into a usable, low-cost wideband SDR.