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QuadRF can spot drones and see WiFi through my wall

jeffgeerling.com

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Re: QuadRF can spot drones and see WiFi through my wall

#121

Post by thomashabets2 »

throwaway85825 wrote: post #42
mikeweiss wrote: post #41

Earlier quoted context omitted.

Whos paying the telcos for those 5G connections and also has the FCC been degraded so much that they would allow for undeclared radios in consumer products?

Secret 5G is not as common because there is a huge incentive to resell the free service. Maybe with eSIM it will be harder. Kindles uses to have a free data plan SIM.

> huge incentive to resell the free service

Not all mobile data APNs go to the Internet. You can't resell an IP service that lands on an RFC1918 network with exactly one IP:port available; the API endpoint.

Not saying I've seen this in devices, but I have built and run mobile data networks with private APNs.

Re: QuadRF can spot drones and see WiFi through my wall

#122

Post by stackedinserter »

mrtnmcc wrote: post #95

QuadRF creator here. Happy to answer questions! We have a quick demo video as well: https://m.youtube.com/watch?v=QvniJk3uNyA Along with a deeper dive video: https://m.youtube.com/watch?v=zdJ9Tbm8ALg We didn't give Jeff great direction on camera alignment calibration or setting the radio gain but he seemed to mostly figure it out. We're improving the UI based on his suggestions (it's open source so you can customize…

That is super cool, man.

Do you have a demo for that 240 elements assembly?

Re: QuadRF can spot drones and see WiFi through my wall

#123

Post by digdugdirk »

mrtnmcc wrote: post #95

QuadRF creator here. Happy to answer questions! We have a quick demo video as well: https://m.youtube.com/watch?v=QvniJk3uNyA Along with a deeper dive video: https://m.youtube.com/watch?v=zdJ9Tbm8ALg We didn't give Jeff great direction on camera alignment calibration or setting the radio gain but he seemed to mostly figure it out. We're improving the UI based on his suggestions (it's open source so you can customize…

Super cool! I noticed you had a blurb about it being used for mesh networks? Could you please go into more details/provide links to resources to learn more about that?

Re: QuadRF can spot drones and see WiFi through my wall

#124

Post by thomashabets2 »

RealityVoid wrote: post #93
ac29 wrote: post #38

Earlier quoted context omitted.

Phased array radars are export controlled in the US. It doesnt mean its illegal to build or own, but it might be illegal to sell in some cases

This is not a radar, only a receiver.

It can still be in scope:

> Direction finding equipment for determining bearings to specific electromagnetic sources or terrain characteristics specially designed for defense articles in paragraph (a)(1) of USML Category IV or paragraphs (a)(5), (a)(6), or (a)

ITAR part 121.

The "specifically designed for defense" probably makes this OK, but IANAL.

Re: QuadRF can spot drones and see WiFi through my wall

#125

Post by michaelt »

varjag wrote: post #107
squarefoot wrote: post #90

Earlier quoted context omitted.

Brute force wide band jamming would be easy too and would make hopping ineffective. Unless drones use self tuning antennas to overcome losses, they can't hop too far away from the antenna resonance frequency, which makes jammers job easier.

Jamming broadband is a lot more energy expense than frequency hopping. Orders of magnitude.

I mean, drones trailing fiber optic cables are widely documented https://en.wikipedia.org/wiki/Fiber_optic_drone

So I’m pretty sure avoiding jamming by a military adversary is not trivial, even with frequency hopping and suchlike.

Re: QuadRF can spot drones and see WiFi through my wall

#126

Post by mrtnmcc »

digdugdirk wrote: post #123
mrtnmcc wrote: post #95

QuadRF creator here. Happy to answer questions! We have a quick demo video as well: https://m.youtube.com/watch?v=QvniJk3uNyA Along with a deeper dive video: https://m.youtube.com/watch?v=zdJ9Tbm8ALg We didn't give Jeff great direction on camera alignment calibration or setting the radio gain but he seemed to mostly figure it out. We're improving the UI based on his suggestions (it's open source so you can customize…

Super cool! I noticed you had a blurb about it being used for mesh networks? Could you please go into more details/provide links to resources to learn more about that?

Absolutely :) we're working on documenting an awesome Meshtastic demo. Should have a writeup next week to add to the Crowd Supply updates page. Also Roy on our team will be demoing it (along with the RF augmented reality) at Teardown 2026 in Portland if you're in that neck of the woods.

Re: QuadRF can spot drones and see WiFi through my wall

#127

Post by fer »

kristianpaul wrote: post #9

And yet since rtl-sdr times we have passive radars as an option as well https://www.rtl-sdr.com/tag/passive-radar/

Passive radar is fine for gigantic airliners with all regard for efficiency, none for radar cross section, and that fly above most obstacles. For drones you might be trying to scratch signal not only from below noise floor, but at the edges of quantization.

Re: QuadRF can spot drones and see WiFi through my wall

#128

Post by varjag »

michaelt wrote: post #125
varjag wrote: post #107

Earlier quoted context omitted.

Jamming broadband is a lot more energy expense than frequency hopping. Orders of magnitude.

I mean, drones trailing fiber optic cables are widely documented https://en.wikipedia.org/wiki/Fiber_optic_drone So I’m pretty sure avoiding jamming by a military adversary is not trivial, even with frequency hopping and suchlike.

FPV drones in the Russian war are generally pretty dumb devices, there's usually no frequency hopping involved to begin with. They have a lot more in common with baby monitors than with modern military comms.

Re: QuadRF can spot drones and see WiFi through my wall

#129

Post by mrtnmcc »

stackedinserter wrote: post #122
mrtnmcc wrote: post #95

QuadRF creator here. Happy to answer questions! We have a quick demo video as well: https://m.youtube.com/watch?v=QvniJk3uNyA Along with a deeper dive video: https://m.youtube.com/watch?v=zdJ9Tbm8ALg We didn't give Jeff great direction on camera alignment calibration or setting the radio gain but he seemed to mostly figure it out. We're improving the UI based on his suggestions (it's open source so you can customize…

That is super cool, man. Do you have a demo for that 240 elements assembly?

We should have a video about MoonRF once we finish the QuadRF mass production, look for it ~ early September! Will be legendary! You can read on how the multi-tile synchronization and calibration works here: https://QuadRF.com/docs/#phased-arrays

Re: QuadRF can spot drones and see WiFi through my wall

#130

Post by mallets »

mrtnmcc wrote: post #95

QuadRF creator here. Happy to answer questions! We have a quick demo video as well: https://m.youtube.com/watch?v=QvniJk3uNyA Along with a deeper dive video: https://m.youtube.com/watch?v=zdJ9Tbm8ALg We didn't give Jeff great direction on camera alignment calibration or setting the radio gain but he seemed to mostly figure it out. We're improving the UI based on his suggestions (it's open source so you can customize…

The really intriguing part is the "Custom ADC" here, seems like some kind of 1-bit ΣΔ oversampling ADC (704 MSPS?). Single differential transistor, and captured by FPGAs LVDS RX.

Neat way to reduce cost and pin-count? But I think the typical FPGA clock tree has poor jitter performance. Not using the internal PLL(s) might help with spurs but the clock buffers are unavoidable.

The documentation mentions it's likely further degraded by noise from switching regulators. Oh the joys of hunting RF noise sources.

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