Turn a WiFi 7 Router into a 320Msps Software Defined Radio Receiver

The project converts a Gemtek W1700K Wi‑Fi 7 router into a wideband software‑defined receiver by replacing the radio firmware and running a custom SoC stack. The MediaTek MT7996 radio captures raw 14‑bit complex IQ up to 320 Msps (with a 640/2 mode yielding flat response to ±155 MHz but folding beyond), and an Airoha AN7581 SoC streams the data over 10 GbE. It supports 2.4, 5 and 6 GHz bands, on‑the‑fly retuning (~1 ms), LO grids of a few hertz, AGC or manual LNA/baseband gain, and 20-320 MHz analog filtering. The radio DMAs into a 1 GiB ring in SoC DRAM and the kernel exports 8 KiB zero‑copy UDP datagrams; to fit the link half the slices are packed to 28 bits per sample pair losslessly.

The software stack includes a ROM patch and radio firmware that bring the radio up without vendor code, U‑Boot and Linux on the platform, a kernel driver handling firmware download/DMA/10 GbE export, and host tools: a stream service that provides shared‑memory complex int16 IQ to consumers with optional decimation roll‑off correction, a spectrum server producing 262,144‑point FFTs at up to 100 frames/s with a browser UI, and a recorder. Installation requires a W1700K, a 3.3 V serial adapter, Ethernet to LAN3, and a 10 GbE NIC to WAN; install replaces the stock OS but first backs up NAND. The firmware is receive‑only; use attenuation before connecting sensitive instruments. License is MIT except kernel/U‑Boot components under GPL.