QuadRF can spot drones and see WiFi through my wall

The QuadRF (pictured above) a phased-array radio built around a Raspberry Pi 5 and an FPGA board with picosecond-level timing. It does advanced signal processing and beamforming.
It can see WiFi through walls and track drones in flight.
If the open source community can come up with something like this, just imagine what governments are capable of.
When you plug a computer into a network, tools like Wireshark can show all the hidden traffic you might not even know is there. WiFi packets are the same, but those travel through the air, allowing snooping without physical access.
The QuadRF has built-in software that can stream and decode RF, and you can pipe it out to a more powerful computer for things like WiFi traffic analysis.
I mention this not to scare you—governments have had tools like these for years. It's just better to know what's possible and expose bad security practices than to ban useful tools like these. So if you're in the CIA, don't get any ideas.
To the Moon
After spotting QuadRF on Hackaday, I reached out to Martin McCormick, who's been working on QuadRF as part of a bigger project: a Moon-scale antenna array, capable of EME (Earth-Moon-Earth) radio experiments and radio astronomy.
I think Martin took inspiration from Dishy, SpaceX's original Starlink terminal. (Makes sense, since Martin worked at SpaceX on the team that built Dishy!)
Instead of locking this phased array antenna system into a proprietary satellite system, licensed operators will ideally be able to chain multiple QuadRF modules together for interesting radio experiments, with up to 1.15 MW EIRP—basically, a massive amount of directional antenna gain, for high power RF fun.
But QuadRF is scaled down to handheld-size, and while it isn't powerful enough to send a signal to the moon, it's still quite useful in local SDR applications and visualizing the RF environment—at least in it's frequency range of 4.9-6 GHz.
Testing QuadRF
But I specifically asked Martin if he'd be willing to send over a prototype QuadRF for my Dad (a retired broadcast radio engineer) and I to test.
I had already placed a pre-order on Crowd Supply (where a basic kit is $499), but I wanted to see if QuadRF was really as useful or intuitive as it seemed from the videos ScaleRF posted.
Spoilers: it's still a little rough in the UI department, but I was blown away by how well it works. Especially considering everything's running on a Raspberry Pi 5.
When you turn it on, the Pi boots up and creates a WiFi hotspot. You connect to that, and visit http://quadrf/
. That page runs a VNC session in your browser, where you can launch apps from GNU Radio to SDR software, and even their custom AR (Augmented Reality) RF visualizer.
The AR visualizer is the most interesting included software, despite being less useful for real-world SDR applications.
The UI is a little rough, but you can adjust the alignment between your camera and the phased array, and the gain of the receiver.
Then it will visualize frequencies from 4.9-6 GHz as colorful 'blobs'. The scale is not shown on the display in this early version, but from my testing around the studio, my 5 GHz WiFi network (which was running on Channel 100, or around 5.5 GHz) showed up light blue. Neighboring WiFi networks were showing up red or green.
If you order the Mobile Expansion Pack, it incorporates a battery power pack, and a handheld phone mount, so you can walk around analyzing part of the C-band in real-time.
My Dad and I flew his DJI Mini Pro 4 behind the studio, and the QuadRF had no trouble picking it out of the sky. As it flew away, I had to increase the gain to keep seeing it; it would be nice to have AGC or an easier gain control as the UI was a little clunky when carrying around the contraption.
It sounds like the crowdfunding campaign is already beyond expectations, and they'll be switching the enclosure to an injection mold (the version I have is 3D printed).
Raspberry Pi 5 MIPI for high-bandwidth RF
One aspect that intrigued me was the use of the Raspberry Pi's MIPI lanes for low latency SDR streaming I/Q (In-phase/Quadrature) at data rates over 5 Gbps. From the QuadRF Documentation:
The novel approach of streaming I/Q over the Pi’s camera and display FFC MIPI connectors has many benefits. MIPI can handle >5 Gbps, low-latency, full-duplex data transfer through the Pi’s RP1 chip. It is simpler and more reliable than USB, adds almost zero hardware cost to the RF board, and can sustain hundreds of MSPS of I/Q with no hiccups or sample loss. Considering cameras and displays are the ultimate form of high-bandwidth signal streaming, it makes sense their standard digital interface is a great match for SDR! We think the industry should adopt it more widely!
It sounds like they had to reverse-engineer the MIPI protocol used on the Pi 5 to do this (since it goes through the RP1 chip), and the way it's architected, you can daisy-chain multiple QuadRF modules together, letting each module calculate it's own phase shift.
I'm not sure how that will work in practice, but it sounds pretty neat. PCIe could probably work in a pinch, too, but this implementation frees up the PCIe connector in case you want high speed storage or even higher speed networking than the Pi offers.
Conclusion
As with all pre-production gear I test, take everything I've shown with a grain of salt. And with any crowdfunding campaign, if you back it, don't expect the QuadRF to show up on your doorstep overnight.
I was initially skeptical about how useful and fun this little handheld phased array could be, but after using it for a week, I can't wait until the one I pre-ordered ships!
Comments

Facts Only

* QuadRF is a phased-array radio built around a Raspberry Pi 5 and an FPGA board with picosecond-level timing.
* It can see WiFi through walls and track drones in flight.
* The system has built-in software to stream and decode RF data.
* The system allows piping RF streams to more powerful computers for analysis.
* A larger project involves a Moon-scale antenna array for EME radio experiments.
* Testing involved using the device with a retired broadcast radio engineer.
* The system visualizes frequencies from 4.9-6 GHz as colorful 'blobs'.
* One tested configuration included a battery power pack and handheld phone mount.
* The design uses Raspberry Pi's MIPI lanes for low-latency SDR streaming of I/Q data over 5 Gbps.

Executive Summary

A phased-array radio system called QuadRF is built around a Raspberry Pi 5 and an FPGA board, utilizing picosecond-level timing for advanced signal processing and beamforming. This technology has the capability to detect WiFi signals through walls and track drones in flight by analyzing RF data. The system incorporates built-in software to stream and decode RF, allowing output to more powerful computers for traffic analysis. Furthermore, the system is being explored for larger applications, as part of a project involving a Moon-scale antenna array capable of EME radio experiments. Testing involved using the device with a retired broadcast radio engineer and another individual, demonstrating its ability to visualize frequencies between 4.9 and 6 GHz as visual patterns. The underlying architecture leverages the Raspberry Pi's MIPI lanes for low-latency SDR streaming of I/Q data over 5 Gbps.

Full Take

The discussion surrounding QuadRF reveals an underlying tension between accessible, powerful open-source technology and potential governmental capabilities in signal intelligence. The narrative frames the existence of such tools as a double-edged sword: while it points to what is technically possible for open research and visualization, it simultaneously invokes fear regarding misuse by state actors, which is explicitly addressed by cautioning against seeking this knowledge from official sources. The progression from localized SDR applications to theoretical deep-space radio astronomy experiments illustrates a pattern of capability scaling driven by foundational hardware advancements, where small components can be integrated into massive conceptual systems. A critical observation is the focus on reverse-engineering and leveraging existing digital standards, specifically the MIPI protocol for high-bandwidth streaming, suggesting that innovation in this field relies heavily on exploiting embedded hardware interfaces rather than purely novel physics breakthroughs. The implication is that control over these capabilities—the ability to map the RF environment non-invasively—is shifting toward those who master these low-level data pipelines, raising questions about the distribution of signal sensing power and the necessity for frameworks governing the deployment of such sophisticated sensing technology. What avenues exist for ensuring that the pursuit of novel RF sensing technology remains channeled toward beneficial scientific advancement rather than purely surveillance capabilities?

Sentinel — Human

Confidence

The text reads like an enthusiastic technical review blending open-source hardware exploration with anecdotal testing, characteristic of an engaged hobbyist sharing their discovery process.

Signals Detected

Sentence length variance is erratic; use of personal anecdotes and colloquialisms ('blowing away,' 'just imagine') disrupts uniform rhythm.

Strong idiosyncratic emphasis on testing, personal experience, and skepticism mixed with technical exposition, lacking the smooth, neutral balancing of typical objective reporting.

Flows logically from a product introduction to expert context, testing, technical deep-dive (MIPI), and a concluding caveat, showing the structure of an enthusiast review.

Specific details (e.g., specific hardware mentions like Raspberry Pi 5, Crowd Supply pricing, mention of Martin McCormick and SpaceX context) suggest direct involvement or deep immersion, making it hard to attribute as pure fabrication.

Human Indicators

Heavy reliance on first-person perspective ('I reached out,' 'I had already placed') and subjective evaluation ('blown away,' 'a little rough'), which contrasts with typical objective journalism.

The inclusion of personal testing protocols (asking Martin to send a prototype) and financial context (Crowdfunding, pre-orders) anchors the text in lived experience rather than pure reporting.