5 ms·

Any RF engineers know how feasible it would be to take a yagi or other directional antenna and put it on a gun stock and make an RF jammer that could be directe

Any RF engineers know how feasible it would be to take a yagi or other directional antenna and put it on a gun stock and make an RF jammer that could be directed at drones? I was once testing a quadrotor that we built for IED detection with a group of marines, and we discovered that the metal detectors that the IED teams were carrying were able to completely fry our electronics from a couple of feet away. I'm guessing the power required to do this from 100s of feet away is significant, and the FCC doesn't take kindly to these sort of activities, but it doesn't seem crazy if you only need a short but intense burst.

reitanqild 12y ago
Related: US Navy already have a real laser gun that was shown melting down an approaching UAV.
nl 12y ago
I worked with the team that built metal detectors used by the USMC (possibility not the ones you used - there were a number of different kinds in use), and I'm very very surprised they fry anything. They are based on CE certified consumer detectors, which have to pass pretty strict emissions tests. I could imagine some interference though.
semi-extrinsic 12y ago
I would imagine taking apart a microwave oven and pointing the magnetron waveguide into a parabolic dish could give you a decent drone killer - a cheap, compact AC powered 1 kW 2.4 Ghz jammer should do some damage.
- walshemj 12y ago
  You would have to make sure you don't get in the beam - you could give your self some nasty burn/radiation injuries with that set up And the FCC would be having a word with you they don't allow civilians to run things that hot you'd be looking at 20-24 dbi
  - semi-extrinsic 12y ago
    I obviously wouldn't recommend doing this without proper RF safety training and experience. Regarding the FCC: Assuming a nice narrow pencil-beam aimed at space, would they care much?
    - Vexs 12y ago
      Doubt it, but getting a pencil beam is nigh impossible with radio, there's going to be leakage somewhere. Also, you'd have a bunch of physicists asking about how you got a beam that thin.
      - semi-extrinsic 12y ago
        I haven't actually done the math, but for a parabolic dish which is much larger than the waveguide diameter, shouldn't you get a very narrow beam? Isn't that how microwave uplinks like the Ubiquiti airFibre5 can give you wireless networks at gigabit speeds over hundreds of kilometers?
    - walshemj 12y ago
      Running a slightly hot 200mw pcmia card for warflying or war rocketing probably not but I think 1.2kw with a gain of 20 from the antenna they might.
sqeaky 12y ago
What about skipping the RF jamming and frying the electronics just like the IED teams did. Maggie Jauregui did a talk at defcon about this: https://www.youtube.com/watch?v=hT9LwyjpfzI https://www.youtube.com/watch?v=hT9LwyjpfzI Wired did a write up about that talk: http://www.wired.com/2014/08/this-hackers-radio-can-fry-your-hair-dryer/ http://www.wired.com/2014/08/this-hackers-radio-can-fry-your...

reitanqild 12y ago

Related: US Navy already have a real laser gun that was shown melting down an approaching UAV.

nl 12y ago

I worked with the team that built metal detectors used by the USMC (possibility not the ones you used - there were a number of different kinds in use), and I'm very very surprised they fry anything. They are based on CE certified consumer detectors, which have to pass pretty strict emissions tests. I could imagine some interference though.

semi-extrinsic 12y ago

I would imagine taking apart a microwave oven and pointing the magnetron waveguide into a parabolic dish could give you a decent drone killer - a cheap, compact AC powered 1 kW 2.4 Ghz jammer should do some damage.

walshemj 12y ago
You would have to make sure you don't get in the beam - you could give your self some nasty burn/radiation injuries with that set up And the FCC would be having a word with you they don't allow civilians to run things that hot you'd be looking at 20-24 dbi
- semi-extrinsic 12y ago
  I obviously wouldn't recommend doing this without proper RF safety training and experience. Regarding the FCC: Assuming a nice narrow pencil-beam aimed at space, would they care much?
  - Vexs 12y ago
    Doubt it, but getting a pencil beam is nigh impossible with radio, there's going to be leakage somewhere. Also, you'd have a bunch of physicists asking about how you got a beam that thin.
    - semi-extrinsic 12y ago
      I haven't actually done the math, but for a parabolic dish which is much larger than the waveguide diameter, shouldn't you get a very narrow beam? Isn't that how microwave uplinks like the Ubiquiti airFibre5 can give you wireless networks at gigabit speeds over hundreds of kilometers?
  - walshemj 12y ago
    Running a slightly hot 200mw pcmia card for warflying or war rocketing probably not but I think 1.2kw with a gain of 20 from the antenna they might.

sqeaky 12y ago

What about skipping the RF jamming and frying the electronics just like the IED teams did. Maggie Jauregui did a talk at defcon about this: https://www.youtube.com/watch?v=hT9LwyjpfzI https://www.youtube.com/watch?v=hT9LwyjpfzI Wired did a write up about that talk: http://www.wired.com/2014/08/this-hackers-radio-can-fry-your-hair-dryer/ http://www.wired.com/2014/08/this-hackers-radio-can-fry-your...