Hmm, he’s usually all over this kinda stuff like a rash.
Probably contemplating how one might build such a thing using only materials found on the street during a protest. Macgyver style.
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Hey, even MacGyver gets worn down from time to time 
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See, while I enjoy the odd ‘subversive conversation’ this is where I get a tad concerned. They aren’t a nut with a gun, they are a Person. Perhaps poorly trained, perhaps badly guided.
But I just can’t stand dehumanizing someone even if you don’t like them (and yes, that is what ‘nut with a gun’ is)
–edit–
i just saw that all of my ‘nut’ words were turned to ‘but’. as in, ‘but with a gun’. i had a mighty giggle at that.
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A butt with a gun?
Sorry, couldn’t resist the softball.
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This thread is hilarious, but if I were you I’d be even more paranoid than usual. 
Maybe the technical expertise and anyone who solders up the prototype of this hypothetical and non-existent device ought to be well outside of the US … Don’t look at me though, I’d only succeed in making local sheep farmers lose their flocks even if it works.
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Nut with a gun might sound a bit harsh, but it’s hardly a neutral stance that they are armed and sent to wander around, literally looking for trouble.
My thinking is that a cop who has real civic duty is still going to be motivated by such sensibilities whether their radio works or not.
But the typical police department/state mentality is to push the officers in the field to control the public at all costs. And they do this by offering the assurance that there is a practically unlimited amount of backup at their disposal. And this is what enables the population of violent and authoritarian asshole cops to do what they do, Being required to deal with their public directly actually does seem to result in the possibilities of more mutual respect.
My reference to superior numbers taking on police was for examples like the video in the other post, where rather than keeping people safe, they become belligerent and violent. Which happens quite often, because they are not made accountable. In my experience, making them deal with you as a person instead of as a resource for their bureaucratic machine helps.
edit: To be perfectly clear, I do not advocate violence against police people, or anybody else. But I think that those who are engaged in acts of violence should be forcibly restrained for people’s safety. And I do not make exceptions for police or other officials. I hold them to a high standard. Unfortunately, most of the times I have been threatened or subjected to violence has been by police. Also, I have spent some time investigating large urban police departments from within, so I am wary of giving them any autonomy. None of this prevents honest, conscientious people in police work from doing a respectable public service.
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I cometely, wholeheartedly agree.
Changing the narrative of “everyone is hiding something” and “I literally need to fill a quota” to dealing with people goes a looong way to fixing the problem you describe.
And now, back to radios 
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This sounds like barrage jamming. You’ll need a lot of radiated energy and even then you have to choose the band…
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A common AM receiver should do the job. Wideband transmissions won’t need accurate tuning, too.
If you use a computer with a soundcard as a decoder, all sorts of automated receiving become possible. Otherwise you can just use a modified Morse, with doubled sub-symbols (e.g. long-short pair being a dash, short-long being a dot, or so, with shorter spacing between them than between the dash-dot symbols. Or, if you use a shared timebase (e.g. GPS, but be careful to not jam your own timebase source), you can even use a pseudorandom sequence of timeslots; a pulse in the timeslot equals one, a pulse just a little delayed equals zero, a pulse that does not fit into the 1 or 0 position or both positions being empty equals missing symbol.
It’s illegal only if you get caught. Don’t be enough of a nuisance to be worth going after. If your tests get dismissed because they are about as annoying as a fridge motor switching off and on, you’re likely to be below the being-noticed threshold.
Steady operation will get you caught. A second here, or three seconds there, preferably when everybody else sleeps, won’t attract much attention and with computers and digital scopes for recording the data for further analysis you can get the most from the tests.
I once managed to kill a TV reception in probably couple 100s feet range, with a corona discharge on a diode multiplier on a breadboard. These things happen even if you don’t want.
Everything is tunable. The old spark gap transmitters used the antenna dipole dimensions for this purpose. A LC resonator will do wonders. A spark-based Tesla coil is a good example; the spark provides a wide range of frequencies, the LC circuit of the primary side then selects one and amplifies it by resonance.
It would.
A smarter way is spending the jammer energy at shorter times, comparable with symbol or message timing of the undesired transmission. You don’t have to jam for all the time if you can just damage the packets beyond error-recovery, or damage the speech beyond understandability. Or even just target the link-maintenance packets; the Marriott wifi shenanigans are a nice example of highly targeted jamming at the protocol level, with surgical precisions and extremely low total radiated power in comparison with going brute force and microwave-flooding the whole band.
It has a lot of disadvantages. But it has a major advantage of simplicity, and the sparks can be made a visual part of a “subversive art project”.
For plausible deniability, study the ways things can go wrong with EMC/EMI; there should be a plethora of real-world cases of undesired emissions that can be emulated in a bit less undesired way. Everything that can amplify can be tricked to oscillating; indeed, keeping such things FROM oscillating is often a major issue.
You can encode the symbols in a plethora of ways. It may work.
You can transmit FM by bit-banging a GPIO on a Raspberry Pi.
Or there are I2C-controlled oscillators/clock sources that the Arduino could run. Or you can use an analog oscillator, voltage-controlled, and use filtered PWM for control.
“More power, Igor!”
If you correlate the wideband pulses over a chunk of spectrum, you could actually get a quite good, robust communication. Similar somewhat to the “ultrawideband” idea.
You’ll waste a LOT of energy. Focus to specific bands of interest; the batteries are likely to die fast, sooner than the adversary can get an alternative equipment. Jamming the frequencies accessible to the adversary’s common equipment will do a better job than going blanket.
Also, for bonus points, put the jammer on a balloon. That way you won’t have terrain to shield the signal, and you’ll have a line of sight to nearly every receiver.
Certainly worth trying! Though broadcasting too much of soft xrays at once will make a beautiful fireball…
Certainly. A leaky microwave oven can kill your wifi but won’t kill your cellphone. It works both ways.
You can do optical jamming; a stroboscope does wonders with other people’s vision at night. But an infrared strobe light won’t do much - people are not tuned to that frequency, and unless you are in retina-burning powers, you won’t luck out. If other kinds of receivers are targeted, that are tuned to that band, in this case e.g. the night vision gear, you can kill that with the IR strobe without affecting your own unaided vision and negate the adversary’s technological advance. You can do this in a pyrotechnic way too; there are strobe compositions, and there are infrared flare compositions (with rubidium/caesium as the emitter) and they could be combined. (Anybody with a night-vis gear willing to try this out? Experiment needed.)
Get closer to the receiver. Jamming near transmitter will require WAY more energy. The energy per area falls with square of distance, so if you get the jammer-receiver distance to be half the transmitter-receiver distance, you can use quarter the energy to match the transmitter. That assumes isotropic radiating antennas, and you can do much better with directional ones.
Even mad scientists have to SLEEP! (At least sometimes.) 
Well, here I am…
As an additional hint. my nose tells me that a lot of answers will be in military manuals dealing with electronic warfare (the US FM field manuals are a plentiful and free resource), history books about the topic (the Battle of the Beams being one area), and contemporary literature about electronic warfare (Richard Poisel being a suggested author), EMI/EMC (the unintentional jamming), and modern digital radio transmissions (especially the factors that influence encoding and decoding of the data and the noise/jamming/interference sensitivity of the channels). Possibly, for advanced uses, with a look at the phased array antennas (“smart antennas” or “MIMO” or other buzzwords), these things are now encroaching the domestic wifi areas after slaving in military for decades.
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I actually do have some NV gear. When I first got it, I walked around the house in the middle of the night to play around with it and see how well it worked. My brother grabbed all the TV remotes, and managed to point them straight in the lens from across the room. That was really bad. Completely blinded me for a few hours because I’d turned up the photomultiplier tube voltage as high as it would go. I was trying to see if the clock on the microwave would be enough “star light” to light up the whole living room next to it.
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Excellent!
That’s a variant of what I propose. An infrared strobe light - LEDs or lasers, driven with narrow pulses, possibly irregularly spaced (Arduino can generate the sequences easily; or a 555, if regular spacing is to be started with.)
Known problem. Tracer ammo does this too. Attenuated-brightness or delayed-ignition formulations were developed for this reason.
Newer generations should have the feature of limiting the max brightness. If you couple a camera to the NV thing, and feedback the image processing to the photomultiplier tube, you should be able to get an automatic version. Using higher bit depth on the camera and HDR processing will further improve the dynamic range.
Some devices have an automatic gain control for such purpose. Pulsed jamming could target this circuit too, much like the Macrovision videotape copy protection did with similar circuitry in VCRs.
It lights the whole room fairly well, when the eyes are darkness-adapted. At least my eyes.
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Staring into a green Photomultiplier tube output by definition means your eyes aren’t dark-adapted (or won’t be for quite a while) 
It’s a catch 22. I bring my NVGs with whenever I go out night trekking, but rarely use them. I have to baby them and make sure I don’t look at anything bright, and in most cases my normal squishy eyeballs are much higher fidelity running around in the dark, unless it’s raining or there’s a new moon/low moon/late or early moon.
My NVGs are crappy. They were super cheap and are basically a photo tube stuck between two adjustable lenses with a wide-band IR LED light stuck on top of the thing if it’s too dark out.
My favorite use for them is going out into a park in the middle of the night. Sitting quietly on a bench for hours and just slowly looking around and seeing all the animals you never notice without the NVGs. If you turn on the IR illuminator, they’re astoundingly good at lighting up animal’s tapetum lucidum so you can pretty easily pick out all the critters staring at you.
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I call such image tube output “infragreen”.
(Purely technically it is not a single photomultiplier but likely a microchannel plate, an array of photomultipliers. Unless it is even older than this tech, and then it is more similar to a crossover of photomultiplier and imaging tube.)
At some camp there was a night-running game. I used an amber LED as my flashlight, the 90-degree automotive grade one, attached to my cap to shine a bit in front of me. I had pretty good awareness of where I am going, plus unimpaired long-range darkness adaptation. (The wavelength choice was fortunate, as it did not kill scotopic vision. It was also sort of forced, as there were no white LEDs back then. If I fool only patented a LED flashlight, I have a prototype made in late 80’s with a green LED…) Cf. others with their conventional flashlights, who saw only where they pointed the beam.
Sometimes less light is more.
The tendency of the NVGs to burn out when overilluminated is Da Suck. Too non-robust for my tastes.
Gen.2, likely? I should get some as a photomultiplier for an xray cassette scintillator plate…
…I wonder if such plate, with a photomultiplier, could be used for autoradiography, if the light liberated by a piece of pitchblende or uranium glaze would be sufficient to register… Certainly is not in “conventional” darkness, even with fully adapted eyes.
Also, are there wideband IR LEDs? Isn’t it just a conventional, relatively narrow-band one? (These rigs also use diode lasers, which are way narrower-band in comparison, so the wideband moniker may be the distinction here.)
Awww… 
The mouse infestations (see the video I posted in the mousetrap thread) would look marvelous!
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I guess the illuminator probably isn’t “wide band” It’s probably some frequency in the Near-IR that’s cheap to make a diode for. It’s more “wide angle” than “wide band”, and it’s distance to dispersion is frustratingly short. If you have a clear line of sight the illuminator’s beam is useful only to about 20 meters. Anything further than that, and it’s too diffuse to make a difference.
Also, yes my NV scope is Gen2. (I keep saying NVG, but it’s really a big fat monocular with 5x magnification and a 2" objective lens. I bought it specifically because it had a 55 degree FOV, which was 10 degrees better than everything else at it’s price point.)
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You may like to experiment with those cheapo ebay laser diodes at 808 nm. With even a rudimentary single-lens optics you should be able to get a long-distance, mildly diverging beam.
Combined with a large telephoto lens on the NVG it may work at quite a significant distance.
Also, a thought. What about an autogating function for the gen2 tube? Add an arduino (or perhaps even an analog circuit) to check the cathode current, and adjust the tube voltage? Possibly add a little mirror and a low-res camera to watch the display and use this for multipoint brightness/contrast metering?
A sexy thing would be a homemade gen-4 (okay, III+) tube. The electronics around is easy. The thin-layer coatings of clean materials are another story, and the microchannel plate will need quite a sequence of operations including precision etching. (Most likely some self-assembly method to generate a regular structure of parallel channels in a sol-gel precursor, then dry/fire and etch the gel? The uniform shrinking of the gel during careful drying will make the dimensions of the channels smaller. This may make it possible to 3d-print the plate, too? Maybe using a stereolithography approach, with a sol-gel precursor that solidifies at UV light exposition? Print the block, wash away the soluble precursor, dry, fire?) Then deposit a thin layer of something resistive (carbon? ruthenium dioxide?) uniformly through the channels, and metalize the faces, so an equivalent of a cascade of electrodes with field gradient is formed. (Possibly by PVD or CVD, or maybe by sol-gel dip-coating?)
(One of the industry methods for the MC plates is fusing together a block of glass fibers with different core and cladding, then cut the block into plates and etch away the cores.)
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I can’t exclaim this reply enough: WINK!!!
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I don’t see well under the best of circumstances. I’m not blind or even “visually impaired” I’m good enough to pass the driving test, and I can shoot okay, but on an a 28" PC monitor I can’t tell the difference between 1080p and 4k. At all. And I go night blind pretty easily.
What I want to do is lean echolocation because it works beautifully for people who are totally blind. But I fear I see too well and am too much of a wimp to lean it while I’m sighted so well.
I see relatively well (got glasses but not really needing them except for very long distances). Still, I am watching the LASIK tech progress; Tiger Woods got eyes tweaked to 20/15, and some say you could get up to 20/8. Hawks have 20/2 vision, for the animal comparison.
Echolocation could be interesting.
Thought: immersive VR with synthetic vision. Think Oculus Rift, showing image reconstructed from sonar and/or radar, optionally with stored map data. Could be interesting for piloting aircraft in zero visibility. Or, if wearable instead of being fed with vehicle-mounted sensors, for zero-visibility diving.
One trick that could be tried with the night-vis rig. Those low-visibility IR-reflective uniform patches. Outside of the US they can be difficult to buy; the idea I have is finding some kind of a black permanent marker (or other ink) that is IR-transparent, and use it to coat a retroreflective foil.
(Of course that the marker vendors do not provide spectral data for their inks. So a trial-and-error approach has to be used.)
(Some access/ID cards use a similar trick. The black strip that looks quite like a magstrip is an IR filter, and there is a barcode underneath.)
Ideally, when the tech comes, I’d just go under the knife, have them pop out my stupid goo-ball eyes and implant something better like what Batou has in Ghost in the shell. Mulrispectral cameras that see from at least far infrared to far ultraviolet possibly with sensitivity to x-rays and particle radiation. It’d be nice to see alpha and low energy beta.
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I fully agree with that sentiment. Once it gets at least into early beta version, I wouldn’t mind one of my own.
(What is puzzling me is why in the ST:TNG universe Geordi La Forge is the only one with the multispectral/hyperspectral visor, and others stick with their grossly inferior Mk.1 eyeballs.)
And the cam tech is possible, even in the form factor.
The bottleneck here is the brain-computer interface. Luckily a lot of research is going on there, both on BCI in general and on all sorts of neuroprosthetics.
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I actually am currently invested financially in BCI research. I’m vested in a University of Washington lab. Not much money, but enough to pay for a few rats. Or maybe a non-invasive electrode cap for some kind of monkey or ape.
