Police find electronic signal-jamming device inside California home | Hacker News Reader

Police find electronic signal-jamming device inside California home

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177 pointsCharlesW204 comments

This is a story I heard when I worked at the BBC. Years ago the BBC had many reports of bad reception in a certain part of the UK. Eventually they traced it to a isolated house near a BBC broadcast tower. The resident had rigged up a big induction coil on his property and he was leaching hundreds of watts from the tower's transmissions. He was using the power to run his house lighting "for free", not realizing he was casting a huge detectible shadow. The story says that he was prosecuted.

If anybody has any hard details or can confirm this BBC legend it would make me very happy.

It’s definitely a legend. The amount of usable power you can extract from a radio signal is minuscule even fairly close to a transmitter. The incident radiation on his property was definitely nowhere even near watts let alone hundreds of watts. Nor would an induction coil or any sort work with respect to power transfer unless it was magnetic coupling.

People seem to think of radio waves as a magical power transfer medium but it’s terrible for that. It’s only really useful for information and no magic stories or hype will be changing that.

I thought you were about to tell this story, where an old TV messed up the village internet.

https://arstechnica.com/information-technology/2020/09/old-t...

I heard of a similar story when taking a tour of a local transmition station as a kid. You can light up fluorescent tubes by placing them on the ground under high voltage power lines, so I'd assume something like that is how this would work:

https://www.theguardian.com/science/2004/feb/26/thisweekssci...

https://m.youtube.com/watch?v=cXhZvyGtMrk

Many many moons ago, when I hung out in a group that ran CBs with linear amps, we used to win bets with people by saying that we could light up a florescent bulb without any kind of power source... which we did by holding the bulb near the CB antenna and keying up.

My dad had a story about this happening by accident at his workplace.

There was a lightbulb which wouldn’t switch off. Electrician came in, tested the switch, very confused, took the glowing light out of its socket and it still continued to shine.

you won the bet...by using a power source? :)

They were swindlers, raking in hundreds in cash using scientific knowledge that was indistinguishable from magic to lesser educated minds.

a wireless power source if you will

I'm sorry to say that putting a coil near a tower would only leech what passed through it, so unless the coil was nearly the same size as/bigger than the tower, and right beside it, and the coil was directly in line with the folks reporting bad reception, this is probably a tall tale.

Not true, the coil emits its own radio waves which are exactly 180 degrees phase shifted with respect to the radio tower. Destructive interference could be measured behind the coil, even when not exactly in its shadow.

Wouldn't the coil emit the opposite induced field?

Yes, definitely, but only to the degree that you actually consume it's generated power.

Surely a HF signal is targeted at the horizon and in the event someone close enough did attempt to gather what I imagine would be a handful of Watts via induction they wouldn't be a target of the RF energy so it wouldn't really even work. You'd likely need close proximity like of sight to the mast if have thought

The BBC transmitter in the story was either medium wave, or perhaps more likely long wave, Radio 4.

Really? Because since the 1950s any towers I know of broadcast a range of services that almost always include analogue TV on UHF

This was analogue radio not television.

Along the lines of looking for "detectible shadows", I wonder if "Wardriving for jammers" would prove interesting in Silicon Valley today. Similar to wardriving for WiFi in the early 2000s.

Most people/companies aren’t deliberately causing jamming or interference. But there are consultants that will help isolate these accidents so the issue can be resolved. Unfortunately the name of the company that does this is failing me right now.

Probably not. Signal jammers are illegal to sell, use, or advertise. You wouldn't find very many.

https://www.gps.gov/spectrum/jamming/

I think when I heard it (from a radio ham in the 80s) he was using bales of fence wire in his loft as his coil. Still that detail about powering the lights (not the whole house) though.

Hams used to put light bulbs on the end of their antennas to light up when they keyed down due to the standing wave on the antenna having high voltage at the end. I suspect that was part of the illusion and the story. It is however pointless and frowned upon as it’s actually detuning the antenna.

The version I heard was a farmer where high voltage lines were run through his property and to get back at the power company he buried a large coil of wire directly under the HV lines to power some of his house.

That wouldn’t work either.

People’s misunderstanding of mutual inductance does not surprise me really.

Sharing stories and getting laughs is more important than having every statement uttered in a conversation be literally true. My radio ham friend had some outrageous whoppers.

Oh yes completely. Half of ham radio is stories of the one that got away and that contact you made when your antenna was broken.

it's a news organization, they are rewarded for getting views, not getting the story straight. for more information on that see how Orson Welles went bankrupt. big media is a bigger threat to society than big oil and the islamic state combined. if people remember right, corporation's were super anti internet because of competition. so if you think facebook/apple/whatever is bad, you were obviously born sometime after the 90s, not being mean, its kinda the way things were, there are people who want to restore that order, but technology happens and old establishments have to accept that they can either fight the new establishment or evolve

The BBC isn’t a typical organisation, it is a public broadcaster created by the British government.

Plenty of flaws (is anything ever otherwise?) but it does try to aim at public interest more than eyeball count.

Yeah, the BBC doesn't have quite the same motivations as commercial broadcasting. To be honest it's pretty good if you take it with the caveat it'll always be at least mildly biased not to the left or right but towards the British establishment of the day. They're definitely not as bad for literally just making shit up to get eyeballs on ads compared to many of the commercial offerings.

Being a public broadcaster also means they can serve niche interests in a way that commercial broadcasters can't. For example, they maintain a powerful longwave service so that small and older boats can still get the shipping forecast when they're out of VHF range (and so people who haven't - reasonably enough in my opinion - adopted DAB can listen to the cricket!). They're also one of the most influential international broadcasters, it's nice always having the BBC World Service available in most places I've travelled to even if it's a bit more transparently an instrument of British soft power than the domestic service.

Based on the photo in an article linked to from the original article, the device appears to be this:

https://www.xiaomitoday.com/product/texin-bg-e8/

Quoting from the ad: "The BG-E8 signal jammer weighs only 2.3 kg. The Texin jammer consumes 60W of power and has a single channel 3-4W transmitting power." And costs $119.99.

Further quoting from the ad: “ the humidity of the Texin jammer is 30-95%.”

I understand that they are trying to describe the environmental conditions under which it can operate (probably) but it made think of a deliciously moist signal jammer. :)

I understand why they would have a humidity max, but why do they care about the min?

(Just guessing, but) excess static electricity, maybe?

The cost on this is incredible. The amount of destruction you could do with a handful of those. Rig them up on timers in various parts of a city. Crazy.

The military have ones which can be dropped from air and are much more powerful.

How long do their batteries hold out? (I'm assuming batteries because "dropped from the air".) If they're "much" more powerful (than the quoted 3-4W) then I'd have some serious doubts that they're useful for much more than a short period of time. That said, I can think of operational scenarios where denying your enemy/target radio/GSM access for even an hour might be useful. Still interested to know the operating time, though...

I don't know the details and they are probably classified anyway. I know about the jammers from a person I worked with as a CS student. This was a project on improving frequency assignment algorithms in battlefield radio networks. We (the university) did the algorithms and they (military) did the reality checks on why a theoretically good assignment doesn't work in reality.

The military has phased array radar on airplanes that can wipe out communications over a gigantic swath of spectrum.

For sure. Although i think most people with enough radio knowledge to even go down this path also know how trivial it is to track down the source of interference, even for an amateur with cost-next-to-nothing gear.

In this case the device was operating for months (blocking emergency frequencies?!?!) before they bothered to look for the source. Something on a timer would be much harder to discover due to the intermittent nature.

> In the last week, it had gotten worse with residents reporting disruptions to Wi-Fi, satellite and cell phone service.

I read that to be “They only started looking for it once it started pissing people off”.

Trip a bunch of these in a city during Superbowl. Whoo boy.

There was a story a couple of days/weeks ago on here (sorry I can't find the link) where someone had been phishing their way into iCloud accounts and downloading all the photos from them. Despite making absolutely 0 effort to cover their tracks (not even a VPN),this went on for a very long time before they were caught.

Just because the knowledge is there and there's a paper trail doesn't mean anyone will _actually_ put the pieces together

Keeping them moving would be cheap and trivial - mount them on a bus or truck or something.

This made me think of the movie, “Pump up the Volume,” where Christian Slater has a pirate radio station and at one point he moves all his gear into a moving van to avoid detection.

The Netherlands had pirate radio stations located at sea : https://en.wikipedia.org/wiki/Radio_Veronica

The UK had loads of these at one point, but the really enduring one is Radio Caroline. They were broadcasting from international waters right up until the early '90s when the British government gave itself extraterritorial powers over foreign-flagged ships in international waters (!) in order to forcibly close down offshore broadcasters.

Radio Caroline are still around though, they've actually done pretty well recently with fundraisers. Their old pirate ship is still used for broadcasting but these days instead of using the old valve transmitters aboard they use 4G to relay their signal to (ironically enough) an old BBC World Service site which is then broadcast on 648 kHz with a much more modern unit. They've just been licensed to turn up the power considerably too so they'll be receivable in much more of the UK and northern Europe than they are currently soon.

It's kind of interesting to see new AM stations popping up in what's otherwise a dying band. I've always thought it's a bit short-sighted to get rid of AM because in a real national "shit hits the fan" scenario where power and networking are heavily affected it's an efficient way to reach lots of people. You can even build an AM demodulator out of a razor blade and a pencil if you're in proper trouble! I expect by the end of the decade the only things left on AM will be enthusiasts like Radio Caroline and hobbyist pirates (there's quite a few of these in the Netherlands and Greece).

New Zealand had a Radio Hauraki, also pirates at sea.

https://nzhistory.govt.nz/page/radio-hauraki-rules-waves%3A-...

I enjoyed this one on the same subject:

https://www.metacritic.com/movie/pirate-radio

Great soundtrack BTW.

there was a story a while back about someone being caught with a signal jammer in his van, because he was sick of people being on the phone while driving

Surely this would cause things to be worse as everyone in proximity to this van would start looking down at their phones to figure out why they stopped working

yeah this was pointed out when this was first posted as well. I thought it was on here, but maybe it was reddit.

I think this is the story: https://www.cnet.com/tech/computing/man-put-cell-phone-jamme...

And when that van is in an accident, people can't call 911 or other emergency numbers anymore.

I hope the van driver received a prize. He certainly has my admiration.

I mean, I remember even years ago you could buy a GSM/3G jammer from dealexpress and the like for about $50. I assumed it's the staple of any car thief to kill the tracking signals(although "proper" trackers use rather difficult to jam VHF not GSM)

I can’t imagine you wouldn’t instantly appear in some list just by ordering these.

Why would a random Chinese retailer keep such a list or even coordinate with western authorities?

What makes you think it's Chinese to begin with?

Or wouldn't they take extra 10% cut from CIA for sharing the data?

Why wouldn't they? They have no stake in this. They'll do whatever let's them keep operating. "Sure I sold 40 units to <name> at <address> last week. Would you like his credit card number too?"

>>They'll do whatever let's them keep operating.

But that's the point - western authorities can't do anything to shut them down and Chinese ones don't care either. Sending a list of buyers is effort and takes time....so why bother?

I mean obviously we're just speculating, I just mean that a random Chinese website would have no reason to respond to such a request from say an American authority(and it's probably unlikely that anyone would ask, seeing as in a lot of places just owning such a device is not illegal, using it is)

You'd be delusional to think that largest Chinese retailer has no foreign agent employees working there. Just like at any point time there's probably an Russian, Chinese and some other agent working at Apple, Google, Facebook, Amazon, MS, etc...

>>largest Chinese retailer

I specifically said dealextreme which isn't anywhere near being a "largest retailer". Also with Alibaba you can just message the seller directly. So I don't see how having foreign agents working at a place like Alibaba would help in the slightest.

Either way, like I said, I would be surprised if any agency was spending any effort tracking this, the devices themselves are often legal to own and the cases of abuses seem rare.

They may not respond to polite requests or threats but I expect they respond to US dollars.

lol that product description:

“ Here we have an excellent device for you. Just have a look to understand what it is from the Texin brand. Did you get what it is? I think you got it. Yes, you are right that it is a signal jammer produced by the Texin named Texin BG-E8 which is crucial from different perspectives. If you are in search of a fantastic signal jammer by you can work properly, then I should say that you are in the right place.”

This could be nice to have one on a commute where one person on the train decides to have a loud telephone conversation. And you'll only have to use it for a minute or so; too short for authorities to track you down, and too short to cause serious damage.

What if you jam the railroad communication on accident? Do you know what frequencies the engineer, conductors and operations center is using?

Well first of all, if their service critically depends on wireless communication, then that's bad design.

Further, I imagine you turn up the amount of power of the jammer until the person on the phone gets bad reception.

I don’t know what you mean by critically. But everything from calling law enforcement for pedestrian and vehicle strikes to handling special operations (i.e. single tracking in a work zone) uses wireless communication.

There are also defect detection systems that rely on radio transmissions to indicate if a train is for example dragging equipment.

And if someone in the next train carriage dies because they're having a heart attack and no-one can call for help (including the driver/conductor), you'd be liable for manslaughter.

Loud conversations in a public place are annoying, but guess what? it's a public space, and you don't have a right to quiet there, let alone exclusive control over radio communications. The sheer entitlement in your post is astounding.

I’ve heard of this psychological problem some people have: where they are disturbed by nearby people talking on the phone. Is there a name for it?

The trouble is that half the conversation is missing, involuntarily increasing the attention of bystanders. Lauren Emberson called that 'halfalog'. https://journals.sagepub.com/doi/abs/10.1177/095679761038212...

Some people just want to commute in silence without listening to overly loud work-related calls made by other people.

I’m one of those people, myself. But then I remember that public transportation means that there might be other people around, and we’re not at a concert where people are not allowed to talk, and that I can’t always get what I want, to paraphrase the Rolling Stones.

This looks to be a bit more serious piece of hardware than what you can get on Alibaba.

How does this stuff makes it to the USA?

You do realize that you can order all kinds of things on Alibaba? Or even, just from the internet?

I was importing small PCBs and components from china when I was 15. Most of the time the seller would write "gift" on the package.

If the seller writes "wifi router" on the box, is customs gonna doubt it? Sure, one in every X should be getting checked by whatever department looks out for "dangerous electronics" but it's easier than you think.

If no american is shipping boats of these into ports to sell, I doubt customs even looked at this person's small box with one device in it.

The other common thing is to label it "test equipment".

Well, there were literally the uranium enrichment centrifuges there one day 10 years ago, the page for which I seen myself.

Though they since cracked down on many things

Yeah but they were only three stars.

Parent comment's linked page has a link to Banggood which no longer works, but presumably it did at one point.

I've bought from there myself with shipping to the US, and I doubt every package gets inspected at customs. Among other things they sell a lot of 3d printing and electronics stuff.

In crumpled cardboard boxes liberally wrapped in that distinct yellow tape commonly seen on packages from sites like alibaba and banggood.

There are hundreds of 5G jammers listed on Alibaba: https://www.alibaba.com/trade/search?fsb=y&IndexArea=product...

I stand corrected now. I seen small portable jammers on Alibaba years ago, but so far nothings like I've seen in the link you gave.

My kids have a super cheap battery driven disco ball thingy that completely obliterates WiFi and cellular when it’s on. Amazing what 1.5v and an unshielded motor can do! Took me a long time to work out what was going on. When we worked out the correlation it was super easy to test though. And yeah, turning on that little disco globe just killed the WiFi.

Reminds me of many years ago when my coworker's monitor was flickering. So we replaced the monitor. Same problem. We replaced cords. Same problem. We replaced the computer. Same problem. Eventually we put his monitor and computer on a cart with an extension cord and wheeled it into the hallway. Problem went away.

It turned out his room had bad electrical shielding and magnetic interference was janking up the CRT monitors.

I would say the monitor had the bad electrical shielding…

Actually both.

When you produce electronics, each device must pass an electromagnetic compatibility (EMC) test before you are allowed to legally sell it.

It test both the electromagnetic emission and the electromagnetic immunity of the device. So not only shouldn't the device emit more than a certain level of EM power, but it must also be able to withstand a certain field strength without losing functionality.

There's a limit to how much magnetic field strength a CRT can withstand, unless you shield it well enough that the screen is obscured.

The monitor was fine in other rooms. We brought in a magnetometer and it went off the charts on the wall near the electrical box in that room. The landlord of the building eventually had it fixed.

When working for an ISP I was told a story of a huge amount of noise getting into the system sporadically on a node in a neighborhood. Happened during a certain time only about once a week and only for about 15-20 minutes. They finally tracked it down to some guys electric weed wacker. They bought him a brand new one and took the offending one. I guess it was bringing the service to its knees every time he used it.

I used to play GSGO. I noticed that using the youtube app on a certain iphone 4s would completely kill my latency, adding about 200 ms.

In France l'Agence Nationale des Fréquences (ANFR- the "police" of frequencies) publishes some stories about unwanted interferences (in French).

Latest one:

https://www.anfr.fr/toutes-les-actualites/actualites/les-enq...

Starting points:

https://www.anfr.fr/publications/rapports-dintervention/brou...

https://www.anfr.fr/publications/lettres-dinformation/liste-...

Also lots of opendata about towers, phones and radio measurements all over the country including interactive map:

https://www.anfr.fr/toutes-les-actualites/actualites/les-don...

Someone did a map of all licenced radio links from this data:

https://carte-fh.lafibre.info/index.php?op_init=137

The real lesson here is: if you don't like the cops, you can jam their signals for months before getting caught.

This was more about jamming everyone's signals nearby (cell phone, WiFi, etc.) than about jamming the cops' signals.

The charges they filed against them though relate to impeding the police, not fcc violations or something.

Given that running a jammer like this is illegal, and the fact that the FCC has a help page for law enforcement to rope them into jamming cases, I’m sure that won’t last long.

https://www.fcc.gov/general/jammer-enforcement

Considering the current state of the art (websdr), I’m surprised the FCC doesn’t have a network of SDRs colocated on partner assets (towers) for rapid triangulation of illegal signals (versus the old school method of driving around in a vehicle).

I'd expect cellular companies to have some capability in that area. They own their spectrum, and anything the cellular network didn't put there deserves attention.

Dumb denial jammers like this one are easy to find. All you need is a spectrum analyzer. There are some under US$100 for frequencies below 1GHz. For about $500 you can get up to 6GHz.

There's a procedures manual for this.[1] Basically, send out people with spectrum analyzers. FEMA has some spectrum analyzers on their list of stuff they will buy for first responders. US Homeland Security has annual practice exercises called "JamX" at White Sands Missile Range or some other isolated base to teach people how to find jammers. Jammers are enough of a headache that more responders are getting the gear to find them.

Any military aircraft or ship with electronic warfare capabilities will see a denial jammer as a target. Fundamentals of Naval Weapons Systems says: "This situation is most dangerous for the jamming unit because he is a prime target for all weapons systems and well within the capabilities of Home-on-Jam (HOJ) and Anti-Radiation (ARM) weapons."

[1] https://www.cisa.gov/sites/default/files/publications/safeco...

So putting a jammer in someone else's car could make them a target for military action?

Automatic drone strike

They do, sort of.

http://www.mdarc.org/resources/regulations/fcc-monitoring-st...

TIL!

18F, hello?! You there?

It's me, Margaret.

Probably way easier to get a search warrant quickly from a judge for disrupting police operations and emergency services that way and let the DA up the charges once the person is actually caught (the article says they weren’t yet arrested). I’m sure the investigation is just beginning.

Are FCC charges considered criminal as well?

They’re local police. Easier to just use the disruption to emergency services as justification for a warrant until they figure out who was responsible and can then rope in the feds.

Local PD probably reported to the FCC and you'll see an FCC violation after their investigation is complete.

A quick google search of the product name (BG-E8 5G Signal Jammer) from the pictures in a linked article[0] indicate it costs a few hundred dollars and uses 30W, with a range of about 250m. Wonder how modified it can be, or how varied those specs may be.

[0] https://morganhilltimes.com/police-locate-signal-jamming-dev...

Since it's probably just an SDR internally, I'm sure someone with a bit of RF know-how could put a transmit amp between the antenna and the device.

These are much simpler. Usually just a 555 setup as a triangle wave generator connected to a series of voltage controlled oscillator chips with a small amp, one per antenna.

Oh wow, that's delightfully retro. I love 555 timers.

Not much of a way to build a defense case when the device says "BG-E8 5G SIGNAL JAMMER" in big white letters on the front.

I'm sure this doesn't quite work, but a defense could be around a technicality like radio transmissions being federal jurisdiction or an improper warrant.

The FCC is even more humorless than the local police and levies very large fines, e.g. https://www.fcc.gov/document/fcc-fines-florida-driver-48k-ja... .

I have no reason to believe that the picture in their tweet was the item seized in this instance. They could be using a stock photo. But hey, why worry about tainting the jury pool, right? Guilty!

> But hey, why worry about tainting the jury pool, right? Guilty!

How many people do you think follow that twitter account?

Even if half the citizens have prior knowledge of a case, you'd just pick the jury out of the other half.

It's in the news story. No one need follow that twitter handle just to see those pictures.

God my life would be so much easier if I could just choose which half of America the jury pool came from.

Jury selection is a thing and it is used heavily exactly for the goal you described. Usually the problem is that people with public defenders bullied by the prosecutors settle before even reaching a jury.

The original photo is from the Mercury News and credited to the Morgan Hill police department.

https://web.archive.org/web/20210827050158/https://www.mercu...

Somewhat interestingly, the photo is no longer in the story, hence the wayback link. Though the hi-res photo itself remains:

https://www.mercurynews.com/wp-content/uploads/2021/08/SJM-L...

Why is the police involved in this? In Norway this task and authority is given to The Norwegian Communications Authority (Nkom), that deal with everything regarding the radio spectrum. They have more power to enter people’s homes than the police. Only if they can not enter they can ask for backup from the police.

Generally speaking only US law enforcement has the right to enter a home, and they usually need a warrant to do it (or "probable cause")

The relevant regulatory agency in this case would likely be the FCC, and they are not law enforcement. Law enforcement matters they would delegate to the courts and the police or the FBI

FCC field agents have the authority to enter many sites for inspections and can issue orders or gather evidence used for fines [0]. I’m sure it’s only a matter of time until these field agents are turned in to full police, as the federal government already has hundreds of law enforcement organizations [1]

0: https://en.m.wikipedia.org/wiki/Federal_law_enforcement_in_t...

1: https://www.fcc.gov/sites/default/files/public_enforcement_o...

Probably because they wanted an opportunity to shoot some dogs (sorry, I watched too much HN this weekend).

Edit: https://news.ycombinator.com/item?id=28339867

I have a 40min time limit each day exclusively for HN, shared between iPhone and Mac

I have one in my house too, but I mainly use it for reheating leftovers and popping popcorn.

> “I can’t imagine a Joe Blow citizen having that equipment to be used for anything other than malicious intent,” Morgan Hill Mayor Rich Constantine told KTVU.

I can't think of a reason, therefore it's malicious is pretty shady logic, for sure.

But an empty house with all this tech that has only this one obvious objective, namely EM-shadow the area, does indeed look pretty suspicious.

I'm quite curious now, and hope we get a follow-up on this, to find out what the real objective was.

To stop drones flying over his house, or to block unwanted phone calls. Just two reasons off the top of my head. Outlandish maybe, but reasonable.

Wonder if you could signal jam for market trading advantages? Block an HFT line or commodities data? Just spitballing.

I can just picture a frustrated parent… “I got these because my kids never would get off their phones. After I got these, they did when I turned ‘em on!”

Ok, Far fetched but the thought amuses me.

drivers have done it to get people off their phones. cue "florida man" https://www.engadget.com/2016-05-25-florida-man-fined-48k-fc...

Teacher so students don't cheat during an exam.

police during riots.

burglars during burglary

Or the parent could just enforce discipline

Annnd.. the tweet shows the exact product used.

It's now showing as sold out on shopee.com (maybe it was before though, who knows?)

I run a smart home blog (smarthomepoint.com) and it's surprising how many people email me saying that their Ring cameras randomly stopped recording, and right before someone walked past and pointed a 'phone like device' at their camera.

It'd be interesting to know just how pervasive WiFi jammers are.

I suspect it's a bigger problem than is advertised in the media.

There are no wired communications in our neighbourhood and burglars have been using these for a long time to disable alarm systems. They use broad spectrum ones because alarm systems use anything from radio, wifi, 2g,3g,4g,5g to send info and contact the authorities. Some people have put up jammer detectors hooked into the sirens; it cannot call the police so then better make more noise.

It's ironic that the resident's attempt to hide by using jamming devices is exactly what led police to them.

It might just be someone being scared by the 5g bogeyman.

That would be my guess: fear of radio waves and general tinfoil-hattery. Although, ironically, this is likely more like trying to silence the neighbour's obnoxious music by running a big white noise generator at top volume.

Except that since we can't hear radio, the observed effects look like silence - but it's not radio silence, rather the opposite. If you don't want radio waves, don't run a radio noise generator.

I'm amazed that the FCC wasn't on him in days, or even hours.

The FCC does nearly zero proactive enforcement of its rules (source: I've worked in the radio industry for nearly a decade). Violations are pretty common since there are a lot of rules to follow, though most people do operate properly or at least make a good faith effort to do so.

I’ve read that the FCC will actively pursue reports of pirate stations or other illegal interference, and they’ll drive around the neighborhood in a van to triangulate the offenders.

In fact here’s a list, but it looks like they stopped updating in 2018.

https://transition.fcc.gov/eb/AmateurActions/Welcome.html

A more recent set of actions is here: https://www.fcc.gov/enforcement/orders

The FCC does do enforcement, its just that much of is is reactive based on complaints from other spectrum users. They aren't rolling around making sure that, for example, a license holder licensed for 10W isn't operating at 15W by using a higher gain antenna than originally specified. Those are the sort of violations that are reasonably common, but also are unlikely to impact other users significantly, so generally wont be complained about.

What do you think led to the FCC's failure to address this in days or hours?

Anecdata from other HN threads is the FCC doesn’t really go looking for these, rather it accepts cases wrapped up in nice little bows by pissed off HAMs. Maybe there weren’t any HAMs in range or he didn’t affect their bands.

Nobody reporting it?

I'd like to think, for all their promises of reliability, mobile phone carriers would notice a sudden hole punched in their coverage maps, since they can monitor the signal quality of each device from their central control as they move around the area, and investigate themselves or summon the FCC once they discover it's not natural interference.

Considering the device says '5g jammer' on the front I wonder if this was just some garden variety conspiracy theories gone wrong

Ironically I’d worry about this jammer being powerful enough to pose a mild health impact on people in the vicinity.

You need a lot of power to have any risk over more than a trivial distance - hundreds or thousands of watts.

"I can’t imagine a Joe Blow citizen having that equipment to be used for anything other than malicious intent"

Can tech savvy folks here talk about legitimate uses for having such a device?

The key issue is that any use case that sounds legitimate is still not really legitimate because, as a rule, it's illegal to operate a transmitter without a specific license and in almost every case the condition of that license is that you won't interfere with others.

The difference asserted in that quotes is essentially between "willful malicious illegal activity" and "negligent illegal activity", there's no reasonable possibility that it would have been a legitimate use - as far as I understand, simply importing that particular device would already be illegal - there is an exemption in the rules (https://www.ecfr.gov/cgi-bin/text-idx?SID=a230935ff03941152f...) for "Three or fewer radio frequency devices are being imported for the individual's personal use" but that only applies to specific categories of devices and would not apply to that jammer.

If I were trying to develop a jamming detector or jam-resistant device perhaps I’d order that device. But I wouldn’t turn it on in the middle of a suburb.

"What does a cosmetology school just outside Dallas need with a 5W adjustable cell phone jammer? Blissful quiet in the classrooms, apparently."

https://news.hitb.org/content/texas-beauty-schools-cell-phon...

Something for a future YC startup to pursue?

Blocking exam cheaters

It's illegal to jam signals but it's not illegal to make your classrooms Faraday cages. Some relatively cheap metal mesh put up behind the drywall would be somewhat more expensive but would solve the problem.

That's... actually a fairly decent use case for a signal jammer.

It really isn't. Cheating with cell phones is the same as cheating with a note card except the quality of information.

They aren't less or more detectable than other forms of cheating so there's no need to specifically target phones. Teachers just need to continue doing what they've been doing for decades, looking for cheaters.

Signal jammers are meant to stop the kind of blatant cheating where you take a picture of the problems, send it to a hired test taker on the outside, and receive the answers. (A Google glass like device would be especially powerful at this.)

Not surprisingly if you only use your phone as a digital cheat sheet then an online one isn’t that much better than an offline one.

When they busted a large cheating ring here in Sweden for the national aptitude test the setup involved miniature receivers and transmitters, a central location giving information to all the test sites, and countermeasures to anti-cheat. The cheating was a multi-million operation and the several people involved got multiple years in prison.

One could say that the quality of information is one qualifying difference, also the scale and effectiveness. They were less detectable, and also designed and tested to avoid detection in ways that note cards are not.

> It really isn't. Cheating with cell phones is the same as cheating with a note card except the quality of information.

It really is. Most cheaters aren't going to assume that their phone is going to be blocked and store things locally.

Please do realize that most cheaters are pretty stupid.

However, that still doesn't make a jammer a good idea.

You're missing the point.

People still have to covertly read a small rectangle for the answers to the questions. That's what teachers were looking for before and that's what they're looking for now.

I may be a bit out of touch with all these new fangled things like people working on neural implants, but back in my day dealing with cell phones during exams (and other school activity) involved either a permanent removal of the offending device and/or an instant fail of the test.

You can cheat on an exam without a signal. But people in the area of exam rooms still should be able to call emergency services if they need to.

But if you still really want to block cell signals in your exam room, just hold exams in the basement of a well built building with a lot of metal in it.

As one of the comments above supposes, this may have been a misguided person thinking they'd be shielding themselves from 5g -- protecting themselves from cancer that might be caused by 5g. Obviously the jammer would hurt them more, if energy at those frequencies does hurt humans (60W is a lot to put into a 5g jamming!).

Such an intent would not be malicious.

Another possible use might be to try to dissuade neighbors and phone companies from using 5g in the area. This would mean taking one for the team for a while until they give up. Except they wouldn't give up -- they would go find the jammer and get them arrested.

I can't think of a legitimate use for a 5g jammer.

yes but it could just be mounted somewhere too then it would be about good detective work and people skills but wven then. it can be triangulated to a degree by its radius.

If someone's quadcopter keeps hanging around your windows at night, this would be a good way to knock it out of the sky.

I wonder how effective simply piping the output of one of these cheapo jammers to a Yagi would be at disabling or simply "return to home" area denial-ing drones.

I will admit that I fantasize about having a signal jammer every time someone on a phone nearly crushes me on my bike.

Burglary ?

1a rights

Please say more!

“I can’t imagine a Joe Blow citizen having that equipment to be used for anything other than malicious intent,” says the mayor.

Although illegal and a terrible idea, I can imagine several misguided scenarios. Maybe a parent enforcing no-internet periods for children? Maybe a paranoid trying to block spying signals?

EDIT: Remember the stories from a few years ago, where hotels installed cell jammers to force people to be gouged by the hotel room phones?

Singal-jammers are relatively common. You can buy really good multi channel jammers online. Cellphone/WIFI jammers go from $100 - $1000.

Criminals use them all the time. People have so many wireless security cameras and everyone has mobile phones that jammers are becoming must have.

I guess only thing that made this noteworthy was that the jammer was stationary, used continuously and was easy to find.

This reminds me of this guy from a few years ago:

https://www.nydailynews.com/news/national/chicago-man-arrest...

I gotta admit, I like his style.

Reminds me of the story from five years ago, about the CPA that created his own “quiet car”: https://www.thedailybeast.com/the-commuter-hero-who-created-...

How can one find LOCATION of such active jammer?

EDIT: How can one find location of a jammer? I'm interested in the process and equipment needed to find location of active jamming device in a geographic area. E.g. what police uses and how can an average person like me do the same.

Roughly speaking, you just need a mobile receiving unit, or multiple fixed receiving units, with a reorientable directional antenna. You find the heading where the signal has maximum strength from a few points, and then triangulate.

There are relatively inexpensive Software Defined Radio devices to enable this sort of thing. See:

https://www.crowdsupply.com/krakenrf/krakensdr

https://www.rtl-sdr.com/ksdr/

Other related discussions here on HN:

https://news.ycombinator.com/item?id=28054017

https://news.ycombinator.com/item?id=27857290

See https://en.wikipedia.org/wiki/Direction_finding

If you wanted to do it cheaply and crudely, you at least need a portable spectrum analyzer that covers the frequency range you're investigating and a rubber ducky antenna that covers the frequency range you're investigating and then drive around watching for where the signal strength increases. (Make sure the antenna is outside the car since the metal of the body will interfere with reception of signals.)

Professional spectrum analyzers used for engineering are quite expensive (I'm told that Rigol's SAs are good for the price) but you might be able to get away with less expensive instruments like the RF Explorer or even an RTL-SDR and one of the software spectrum analyzer packages out there, assuming they cover the frequency range you're interested in. By definition, jamming needs to be powerful enough to drown out any competing signals so it should be obvious if jamming is occurring even to relatively low sensitivity instruments.

Your phone can detect the network signal strength. Flip the algorithm on its head: detect the network noise strength – how much radio noise is drowning out any signal. Then just keep walking in the direction of higher bars, and you'll find the jamming device.

Alibaba or any other sketchy importer.

Is it possible to find such jammer with a cheap RTL-SDR and some specific software? Does anyone have some guides as to how you find jamming or interfering devices?

In theory it is fairly simple, you simply go to a number of locations (greater than 3) and record signal strength. That lets you tell if the sender is farther away or closer. You can run the numbers yourself or alternatively throw it at a computer to figure out where some transmitter has to be to produce those transmit powers.

Alternatively, you take your receiver and record signal strength, then you walk and see if it's stronger. You then just walk in the direction the signal becomes stronger in.

>5G SIGNAL JAMMER

Wouldn't surprise me if this was some nutjob trying to avoid cancer from 5g frequencies... by emitting a whole lot of them with their jammer.

Must have been a poorly made jammer or multiple jammers. 5G is sub 6GHz, LTE is sub 4GHz and for Santa Clara county almost all public service and trunked radio systems are sub 1GHz (radioreference has most of the frequencies between 300MHz+ and 900MHz) so whoever had this jammer running was jamming one hell of a wide swath of the RF spectrum. As you said they were putting out way more RF to jam all that than 5G uses.

Edit note: misread article, states "They found two signal jammers"

LTE and 5G sometimes operates pretty close to public safety, for example the 600 and 700 MHz (sometimes referred to as low-band LTE/5G although that's a bit confusing given low band is more often used to refer to low VHF and these are low UHF) are close to the 700MHz public safety bands. There's a similar issue around 900MHz.

And a lot of public safety radio these days is LTE - most cities operate an LTE network on one of the upper public safety bands, and they see extensive use by police and fire for MDTs. Voice is still more often over something like P25 but frequently adjacent to municipal LTE. So even a well-designed LTE/5G jammer might target these bands.

But in general jammers are not precise devices. 5G operates over many bands in a few significantly different parts of the radio spectrum. It's by far easier to emit broadband noise in the right general regions, but that will end up knocking out hundred-MHz wide swaths or more.

> 5G is sub 6GHz

Quick google search suggests otherwise. It appears to depend on configuration but can go over 50 GHz, is that true? Would be a real broad band operation if they're trying to jam all that.

I can't speak to the intentions of the person operating the jammer - if a person were using a jammer believing it to be prophylactic of the effects of radiation by 5G radios it may not be useful to ask what frequencies they were trying to jam.

Anyways, the excerpts from DDG results for the BG-E8 5G list its jamming spectrum as 870MHz to 5850MHz. And for probably 98+% of users that will cover the frequencies in use where they live. The "high band" frequencies (25-100GHz) have a much shorter range, very low penetrating power (essentially you need to have line of sight to the antenna), and really only make sense in very high density areas like stadiums and maybe urban cores.

Thank you, I stand corrected. It seems 5G is all over the spectrum according to the FCC[0]. Not quite sure why I thought it was limited to sub 6GHz for some reason.

[O]: https://www.fcc.gov/5G

Probably because sub6 is the only one that matters to most people. The others are rather useless outside of high density events(think a football stadium and such), as they have next to zero penetration power.

Most 5G phones only supports “sub6” and only few supports “mmWave” standards. These are sort of analogous to “2.4GHz” and “5GHz” in Wi-Fi.

Yes, 5G can operate on lots of different frequencies depending on whether you want high bandwidth or high coverage (or, through careful combinations) both!

Since 50GHz is basically line-of-sight, if you want to jam it, just build a wall!

You can buy products online which claim to jam just about everything. For "testing" purposes of course.

I was wondering what the motivation behind this would be, and I guess this would make sense.

What! You don't understand, no one listens, understands!

It's not the frequency, but the carrier wave. The metal from COVID shots, is reactive to 5G frequencies, thus causing our cells to vibrate, damaging their DNA.

Worse, these vibrations prevent the neuron from firing until the carrier beats, forcing them to fire on demand, slowing thought, and even causing confusion at government mandated times.

This, coupled with in sync video transmissions on cable, can be used to cause a sense of agreeable thought at pro government messages.

They're in our head, they're messing up our DNA, it's all part of a decades long plot to oh god they're here tgey5 at the door I <no carrier>

For the casual reader:

• There's no metal in COVID shots.

• Aerials that react to certain frequencies have to be sized appropriately, so even if they were in the shots they wouldn't fit through (and would therefore be filtered out by) the needle.

• And even if it could, the aerials would be too big to fit in your cells.

• Even if they could, it wouldn't cause your cells to vibrate; RF oscillations don't have a “direction” that alternates, so they can't set off vibrations like that (unless the aerial has a specific shape, but the effect would be tiny (way less than the vibrations from road noise, or clicking your teeth together) even if you put it in a microwave).

• Vibrating your cells doesn't damage your DNA. Putting your arm in a blender wouldn't even damage your DNA! (Proof: singing doesn't cause cancer.)

• The carrier wave is “the frequency”. The signal is transmitted in the sidebands. https://en.wikipedia.org/wiki/Sideband

• You're not going to get something resonating to the sidebands without a phase-locked loop (or similarly sophisticated circuit), which requires more than just metal, and certainly wouldn't fit through the needle.

And that's just the second sentence! This is well-written satire; it's got nearly one fatal error per word, yet it still manages to sound plausible. (Edit: I missed some; I've probably missed more.)

Dunno why the down votes...I thought it was funny.. needed some line noise at the end though :-P (A perl one-liner should do nicely!)

https://news.ycombinator.com/newsguidelines.html

I can’t remember the last time I read a comment on a newsgroup or forum that ended wi<NO CARRIER>

+++ATH0

Another Truth Warrior down...

Too bad you’re greyed out, I thought it was funny!

They probably should hire some Ham radio fox hunt enthusiasts... 6 months is wayyy to long.

Where can I buy such devices? I’d like to hide one in the garden of my neighbors (or maybe my own garden is sufficient), so their Bluetooth speaker stops working. Ideally I’d not like to jam headphones to stimulate good behavior but at this point I’ll take anything.

Chances are the fine for deliberately causing RF interference is more than the fine for causing harmful noise. I looked into this too when I used to share a bus commute with this complete dickhead who thought the bus was a good place to share his taste in music but in my country at least it has some fairly hefty penalities if you're caught and even if you're not, if you don't build it well you might jam emergency communications as well which I'm sure we can all agree is a pretty awful thing to do.

Check the noise bylaws, many cities prohibit the use of speakers that are audible outside the property even if operated outside of quiet hours. If your city has such a statute, you can try talking to your neighbor and/or report it and have the police enforce the noise law. Good luck, I know firsthand how irritating this can be.

They are sold everywhere online, here is an example from a model similar to the article:

https://www.alibaba.com/product-detail/Texin-phone-signal-sh...?

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