A new software-defined radio platform built around the Raspberry Pi 5 treats radio waves as something you can point a camera at. QuadRF, now live on Crowd Supply, uses four coherent antennas to measure tiny differences in signal arrival time and render nearby transmitters as color-coded blobs layered over a live camera view at 30fps. Wi-Fi devices, drones, beacons, wireless cameras, and lab transmitters each show up as a distinct RF source, viewable through a browser on a phone, tablet, or laptop.
The appeal for the open hardware crowd is what sits underneath that demo. The entire software stack ships open source under GPLv2/GPLv3, the antenna and mechanical ecosystem files are planned under CC BY-SA 4.0, and the system speaks the standard SDR dialects rather than locking you into a vendor app. I/Q sample streams can be forwarded over Gigabit Ethernet, USB 3.0, or Wi-Fi through SoapySDR or ZeroMQ, and Scale RF lists compatibility with GNU Radio, SDRangel, SDR#, and similar tools. The full source is hosted at open-space-sdr on GitHub. Only the production RF core and the official factory DSP bitstreams stay proprietary.
That tooling is mature ground to build on. SoapySDR is a vendor- and platform-neutral abstraction layer that most off-the-shelf SDR hardware already targets, and GNU Radio (currently at 3.10.x) bundles soapy source and sink blocks out of the box, so flowgraphs written for an RTL-SDR or HackRF can in principle be repointed at a four-channel phased array. Selected RF sources can also be routed straight into GNU Radio flowgraphs, video decoders, communication modems, or custom code running on the onboard Pi 5, which handles control and local processing.
The hardware backs the software ambition. QuadRF provides four RX and four TX full-duplex digital signal chains, up to 1W of transmit power per antenna, and four swappable dual-polarization antennas supporting RHCP and LHCP. It operates from 4.9GHz to 6.0GHz with up to 40MHz of instantaneous bandwidth per antenna. A Lattice ECP5 FPGA manages distributed DSP and beamforming, Analog Devices MAX2850 and MAX2851 mixers handle up- and downconversion, and a 5.6Gbit/s MIPI link carries data from the RF FPGA to the Pi 5. The ECP5 is user-programmable via OpenOCD or standard JTAG tools directly from the Pi 5 through a dedicated 8-pin JTAG header, making custom DSP bitstream development possible without proprietary toolchain access. A single tile is also designed as a module for larger arrays, with documented open interconnects scaling toward 72-element and 240-element concepts for uses like Earth-Moon-Earth communication, radio astronomy, mesh networking, and satellite links. The CC BY-SA 4.0 antenna release includes PCB CAD and Gerbers for all three array sizes alongside OpenEMS electromagnetic simulation files and MoonRF array structure CAD, so anyone extending or modifying the antenna geometry has a full simulation baseline rather than just the fabrication outputs.
The QuadRF Kit bundles the tile, a magnetic enclosure with a clear front panel, four antennas, the Raspberry Pi 5, a cooling fan, a tripod and mobile handle with smartphone mount, a 27W USB-C supply, cables, and a preloaded microSD card with drivers, calibration utilities, web interfaces, and example applications. An optional Mobile Expansion Pack adds 21700 lithium cells for roughly 5 to 6 hours of receive-only use or 3 to 4 hours under full transmit load. The main kit is priced at $500 (€460), the Mobile Expansion Pack at $150 (€140), and a Six-Pack at $590 (€545). The kit and mobile pack are expected to ship on 2026-09-30, with the Six-Pack listed for 2027-01-14.
