yesterday at 3:32 PM
Nice to see the results match Dr Arthur Bradley, the OG in the field (no pun intended).
https://www.youtube.com/watch?v=aMct99DiZak
For my money, a triple burrito wrap of foil and ziploc gives 90+ dB attenuation plus moisture and mechanical protection.
Also nitpick, but the E1 pulse doesn't fry beefy transformers, instead it's the long-period E3 pulse (seconds to minutes) that raises the grid voltage and overvolts the transformers.
yesterday at 9:59 PM
You mean a guy who sells crap to preppers?
...Who has never published in a peer reviewed journal on EMI or anything relating, remotely, to grid infrastructure or power control, etc?
...Who has zero background in electrical grids? He worked on cables in spacecraft. That does not apply to national electrical grids. Do you ask your dentist for his opinions on brain surgery?
...Who is basing everything off the assumption that none of the last fifty to sixty years of improvements in grid control, monitoring, and protection don't exist?
Neither pulse does anything because modern electrical grids have tens of millions of arresting devices, extensive monitoring, and extensive self protection devices at nearly all levels? At least in no small part to be able to handle the millions of lightning strikes that hit grids?
Every substation you drive by has a controller that watches voltage, current, and frequency and nearly instantly disconnects the substation from the grid if parameters exceed safety margins.
A HEMP would cause widespread electrical outages. It would not fry everything.
yesterday at 3:03 PM
I did a much lower fidelity experiment this past week with one of my kids.
I have some radios I threw in metal boxes on the off chance something like this happened so we’d have some way to get emergency alerts. To check how well it shielded we threw my phone in it and they called to see if it rang. It did.
So we tried some other things - the microwave (worked), a tool chest (didn’t), a faraday bag (worked), miscellaneous storage boxes (didn’t).
Fortunately, the box with the radio was an old box and some paint had worn from the edges. We made a “seal” out of aluminum foil and tried again. It worked.
This only tested high frequency signals and probably doesn’t reflect real EMP risk in any way, but it was fun to do.
yesterday at 4:23 PM
When you say "worked", do you mean the phone worked in the microwave or that the microwave worked as a Faraday cage and prevented the phone from ringing?
yesterday at 4:36 PM
They are saying the microwave and the faraday bag worked as a faraday cage.
The storage boxes and tool boxes did not function as a faraday cage.
today at 12:21 AM
While I appreciate your experiment, a thick enough paper bag would block 5G access for most phones.
yesterday at 3:23 PM
Technically I'm measuring in the "wrong direction" since I would be very surprised if an EMP were initiated inside a trash can in my basement, but shielding works the same in both directions so this doesn't matter.
It really doesn't, with 1.5GHz you're still in near field regime inside the can.
yesterday at 5:46 PM
Yep. The exact placement of the monopole w/r to the close can wall will change the the polarization which changes how will it will get through the imperfections in the horizontal seam slots which will be polarized. And that's ignoring the that different places will be better or worse (vs frequency) for exciting the can's cavity modes (at $frequency) in the first place.
But a long distance high power RF source can have these properties altered too by the type of emission mechanisn, reflections, scattering, etc and items placed in such a faraday cage will be located at good and bad places to excite the cavity mode too.
So it's kind of a wash and probably okay for this kind of test. The fact that the electric and magnetic components of the field aren't in balance (near field) doesn't matter too much.
yesterday at 5:23 PM
yesterday at 4:23 PM
He’s testing penetration from the opposite side regardless of the source location.
Yeah, you put a transmitter inside the can, and a receiver inside the can, and the receiver is gonna get signal.
yesterday at 6:42 PM
As GP pointed out, the problem is that if the source is inside the can, the walls are near the source - where the EM field diverges - whereas with an EMP the source would be far away (hopefully) so the EM field lines would be roughly parallel over the surface of the cage
yesterday at 6:39 PM
EMPs do not affect small devices that aren't plugged in, they simply don't have the size to couple that much EM energy.
What is potentially affected is large power lines, railways, street lights, copper-networking equipment, some industrial systems, etc..
yesterday at 8:04 PM
Nuclear weapon vs extreme solar events are quite different beasts to protect against. I think your statement above applies very well to solar but might not play out that way for the nuclear weapon scenario.
yesterday at 8:11 PM
[author]
I think you're very likely right, and do say so in the post. I thought it would be fun to test how well the trash can worked anyway.
yesterday at 7:04 PM
I use metal cookie tins with lids that seal tightly to store thumb drives and hdds of data, my most recent old phone, emergency crank-and-solar-powered radio, walkie talkies, etc.
I tested it by putting my phone in there, closing the lid, and then calling it. No ring. Then loosened the top and it rang. Tested it with streaming music too.
I tested with the radio too. It played music with top off, and went to static with top on.
yesterday at 6:51 PM
last Thursday at 2:18 PM
last Thursday at 2:46 PM
yesterday at 7:03 PM
As a New Englander, I am not surprised WBZ was the strongest AM signal available. Depending on the weather, you would hear callers from the Midwest and South regularly on a Boston-based station.
yesterday at 3:16 PM
Since you already suspect that any EMP will come from above why didn't this guy simply turn the trash can upside down and place it over the test setup?
There would be no need to seal anything since the can has a continuous rolled seam. Just use a standard trash can instead of one of those kitchen trash cans that likely has a plastic bottom for easy clean-up.
yesterday at 5:05 PM
That wouldn’t help I don’t think. I’ve had very small holes in a faraday cage results in rf leaks - slots thinner than a credit card.
yesterday at 5:12 PM
I see what you are saying and understand that problem but I was picturing something like this type of can from Home Depot:
https://www.homedepot.com/p/Behrens-31-Gal-Galvanized-Steel-...
I use these as planters for my orchard fruit and nut trees. They have no open holes. I have to drill the bottoms or side to add drainage so that the trees don't drown.
yesterday at 8:42 PM
Sorry I thought you meant to leave the lid off.
That would probably work well with the lid on floor, bin over the top.
I work with an MR scanner. Bluetooth seems to work through the cage (or did on the previous scanner I used) and cellphone calls work though it fine as long as the door is just a tiny bit open.
It’s quite interesting to play with.
The cage drops signal 100db (well, that the spec it’s built to).
Rf leaks are the worst. You can run the scanner in a ‘detect rf’ mode to try find any leaks. They can be a pinhole, a faulty light, a poorly sealed escape hatch etc.
A bad one can take a very long time to find and it’s enormously expensive to do so.
yesterday at 9:09 PM
As a geophysicist, I understand your problem. Pinholes, slit length and width, mesh size, etc will all factor into the suitability for use as a signal attenuator. It comes down to the wavelength of the energy that you're trying to block. Common millimeter or submillimeter wavelengths from ordinary consumer devices make it important to take a hard look at your shielding to identify any stray path opportunities. Transmission and reflection coefficients of the materials and the propagation medium, reflection paths, material density properties, etc. All these things will work with or conspire against you.
yesterday at 11:34 PM
With MRI things only ever seem to conspire against.
The more time I spend with it the more incredible it seems that that it ever works.
yesterday at 9:07 PM
a trash can upside down ... on top of what? a shallow mercury bath?
a passing wave, even a distant plane wave, will couple to the EM surface waves of the can surface.
also novices always home in and hyperfocus on reflectivity and transmission attenuation lengths, which works when done properly, but is a complete PITA without using absorbers.
simply placing an unopen plastic water bottle inside the cavity means that any EM energy that does make its way in, would be absorbed, instead of repeatedly reflecting from your perfect metallic reflector walls...
Consider a small 2D patch of metal sheet with some resistivity: any attenuated tails of EM waves will induce currents in the metal, and those currents can flow in all directions in the sheet.
Now consider the same metal sheet with a very fine unintentional slit, while currents can still run parallel to the slit, the metal doesn't admit significant current (ignore electron tunneling across the slit) across the slit, this means a current can circulate around the slit, this is why some of the commenters here point out the issues with slits. Simply placing mating metal lids / doors / ... against metal containers does not guarantee identical conductivity across the formed slit: imperfect planarity (think placing the Alps upside down on the Pyrenees), different metallic phases (annealing etc) at the surface, the spontaneous formation of an oxide layer (aluminum has a thin corundum layer, iron/steels/metals oxidize,...), protective coating layers, ... all contribute to the failure to text-book-reflect an EM waved with a perfect isotropic conductor.
Suppose you wish to protect your empire from an overrun by the barbarians: proper border control is important, but in practice imperfect, so you need a way to absorb or apprehend any barbarians that made their way in.
Thats why you want to place a wideband absorber within your protected cavity. This increases the demand on EMP power to disturb any sensitive devices.
yesterday at 9:26 PM
I will definitely remember your advice about incorporating an absorbing medium inside the device should I ever need any EMP protection.
Thanks for the added context about apprehending those barbarians that find their way inside the containment shield.
yesterday at 10:04 PM
It’s all about the barbarians
yesterday at 5:33 PM
Presumes the floor (or other surface) is perfectly flat, perhaps not the best assumption?
yesterday at 5:52 PM
And that the floor will attenuate any reflected EMP/signal from underneath (should be small in a basement, but ...)
yesterday at 6:04 PM
In a reply to another comment I gave a link to the type of trash can that I was thinking about for the cage.
While there may be imperfections in flatness on standard, uncarpeted floors that can allow RF signal to find a path inside (reflections from below or from other angles as another comment mentions) or you could live in a house like mine where flat had a non-standard definition with lots of slop, I believe that you solve those issues by setting the lid upside down on the floor, placing your apparatus inside the lid, then covering and sealing it with the inverted trash can.
You should have plenty of signal attenuation either way.
yesterday at 7:38 PM
Trash can lids are usually not so flat, which makes the whole thing wobbly. The ones you linked lack a handle on top, but it's a common feature on metal cans.
yesterday at 8:19 PM
From another comment:
>Presumes the floor (or other surface) is perfectly flat...
with your reply to that comment:
>And that the floor will attenuate any reflected EMP/signal from underneath (should be small in a basement, but ...)
I believe that I addressed those issues in my reply to the other poster.
>Trash can lids are usually not so flat, which makes the whole thing wobbly.
Very true but simple to accommodate for even if the wobble has zero effect on its signal attenuation characteristics. If the can that I linked topples in the wind it will not affect the seal at all. That is a very durable can with a dependable grip on the lid.
>The ones you linked lack a handle on top, but it's a common feature on metal cans.
True that handles are common on trash cans. I buy that trash can specifically because it does not have a handle and therefore it has no holes or slits in the lid. The dish shape makes it suitable for use as a shallow, very durable bird bath or water feature for attracting bees and other insect pollinators. When you have a lid like that one you can get a cheap solar-powered floating aerator/sprayer and add a few rocks and a piece of weathered driftwood for perches. Bees, wasps, dragonflies, butterflies, moths, etc will make good use of the small fountain feature. Fountains that I have scattered on my place draw all kinds of insects and birds. A few weeks ago I had a snake slither over to one of them and spend a few minutes dipping its chin for a cool drink.
I plant trees and other plants in the can and use the lid for water features.
yesterday at 5:19 PM
On the topic of Faraday cages: is there a way to make one whose "Faradayness" can be turned on and off at will? I remember hearing that you can do so with current, but I haven't found much info since.
yesterday at 6:10 PM
The simplest solution is to use an actuator
yesterday at 4:10 PM
When apple started doing mac address randomization on the iphone, we used a metal trash can to test that in a controlled environment. It worked quite well for wifi isolation. We did not tape the lid.
yesterday at 4:38 PM
This is a cool test and a great use of (relatively cheap) rtlsdr dongles. Ignoring the "prepper" aspect a faraday cage is genuinely useful thing to have around if you want to play with radio transmitting without any chance of breaking any laws.
A much better faraday cage is matroiska doll nesting of two different size trash cans with a non-conductive platform supporting inside smaller can. The air gap and double conducting surfaces really help. And with the different circumference of the smaller can's rim there'll be a different resonant freq that gets let in. So while the outside seam may pass ~339 MHz without any attenuation the inner seam might pass ~450 MHz and so both unintentional passbands will get at least the minimum ~20dB attenuation per can.
yesterday at 6:38 PM
> It's not totally known what effect an EMP would have on stuff
Sandia wrote a report called, "Did High-Altitude EMP Cause the Hawaiian Streetlight Incident?" - http://ece-research.unm.edu/summa/notes/SDAN/0031.pdf
There's probably a hyper detailed classified study sitting somewhere in a dusty drawer with that data that should probably be declassified. If you'd be down to FOIA it, I'd love to read it!
> With how quickly AI is going basically all futures are weird in some ways. I've been thinking about how this affects me personally, and "try as hard as possible to keep AI from getting us all killed" is pretty high on the list. For me this mostly looks like donations and pandemic deterrence, but I also put some time into thinking about disasters. There are ways AI might go very well, or very poorly, and then there's the "messy middle" where we muddle through and things might fall apart some in the meantime.
>
> The big things here are making sure you have enough water and food for a while, along with critical medications and the standard "prepping" recommendations. But lately I've been thinking about what you might do for other risks, such as engineered pandemics, mirror bacteria, or fire suppression outages. And today, EMPs.
But based on the post, it seems that your threat model is off. The biggest threat of an EMP blast won't be your electronics acting up, but it would be the critical high voltage transformers being taken offline. These transformers have a lead time of months. Weeks in the best-case scenario.
From the congressional research service, https://sgp.fas.org/crs/homesec/R43604.pdf
> Most HV transformers are unique and therefore are designed and manufactured to custom specifications for a specific network application. In 2010, the lead time between an HV transformer order and delivery ranged from 5 to 12 months for U.S. manufacturers and 6 to 16 months for foreign manufacturers, although lead times well over 20 months could be required in certain situations.10 This process may include three to four months for the engineering design alone.11 Since manufacturing generally occurs on a single production line with just-in-time component supplies, advanced production scheduling is important for managing delivery.
>
> Physical assembly is labor intensive, requiring manual winding of the copper wire around the transformer core and frequent engineering checks during manufacturing. Extensive testing of completed units also contributes to HV transformer manufacturing time. The installed cost for an HV transformer depends heavily on its configuration and specific design requirements.
>
> New HV transmission substations can cost well in excess of $10 million, including the cost of transformers and other station equipment. According to the U.S. Department of Energy (DOE), the factory prices for HV transformers typically range from $2 million for a 230 kV unit to $7.5 million for a 765 kV unit, before transportation and installation costs.
It's possible to do that but it's not possible to do that cheaply.
As far as contingencies for EMPs for your personal items go. You can use water as a very effective shielding medium. If you have an average sized backyard swimming pool, and if you can somehow bury something at its exact center i.e. under the pool, then a small box there would survive almost anything. Water is a really, really, really great shielding material.
yesterday at 8:17 PM
> I don't think this is a healthy line of thought, but I don't think most people who think this way are ready to hear that.
Happy to talk about this if you like!
> But based on the post, it seems that your threat model is off. The biggest threat of an EMP blast won't be your electronics acting up, but it would be the critical high voltage transformers being taken offline. These transformers have a lead time of months. Weeks in the best-case scenario.
I agree with you that long-term blackouts are the largest impact in an EMP situation and I should have said something along those lines in my post. I've been thinking a lot about backup power already, and part of what I was looking at in the post is whether I need to take extra steps to protect my backup power options from an EMP (it seems to me I really don't.)
yesterday at 10:53 PM
> Happy to talk about this if you like!
yesterday at 11:10 PM
Sorry, I meant here! I like to talk in public as much as possible (https://www.jefftk.com/p/comment-dont-message)
yesterday at 11:52 PM
Sure. I've interacted with you before and communicated my point of view frequently. See,
https://news.ycombinator.com/item?id=49620746
https://news.ycombinator.com/item?id=49637557
The self-fulfilling prophecy, https://news.ycombinator.com/item?id=49890381
On WMDs, https://news.ycombinator.com/item?id=50293688
An intuitive explanation for why a lot of the hysteria is wrong, https://news.ycombinator.com/item?id=50484072
How the hysteria is already harming the field, https://news.ycombinator.com/item?id=49651727
And the walling off of the global intellectual commons, https://news.ycombinator.com/item?id=50028478
Whereas the real risk of these machines aren't being discussed or countered, in fact the hysteria makes that outcome almost certain, https://news.ycombinator.com/item?id=49252258
https://news.ycombinator.com/item?id=48024901
yesterday at 9:39 PM
This is idiotic.
First off, this isn't Hollywood. You can't put an EMP device in the back of a panel van like in Ocean's 11. There are no non-nuclear weapons that can do the whole "aliens knock out all our electronic devices" schtick.
The effects of HEMPs (ie extremely high altitude nuclear explosions) are wildly overstated and based off Starfish Prime which was in the 60's, with the effects used to scaremonger people ever since. The electrical grid and everything connected to it then, bears nearly zero resemblance to the grid of today and the devices on it. Both the grid and everything connected to it are all much better protected and tolerant of electrical surges. Also, if a country did something like Starfish Prime it would take the US minutes to figure out where the weapon had come from, regardless of what country did it, or what country was hit, because US space command tracks everything bigger than about the size of an apple.
Your cell phone (and nearly everything else around you that is electronic) is designed to handle static electricity shocks which can be 20,000 volts and 10-20mJ. The modern electrical grid is designed to tolerate solar flare storms and more, with automatic protection devices that trip disconnects, and there are millions of arresting devices (like this: https://www.hubbell.com/hubbellpowersystems/en/products/powe...) all along transmission lines and in stations to deal with lightning strikes and so on. Our electrical grids have much more sophisticated monitoring and automatic protection devices. Substations have their own backup power systems to keep control systems running for restarting after a blackout.
Most electronics made in the last 40 years are well shielded for EMI/EMF for preventing & not being affected by interference. That same shielding protects against emp's. Open up any laptop or desktop. fully shielded inside. Nearly every switching power supply has both wide input voltage range but also internal surge protection, and high voltage isolation is extremely common, at least in well made devices. Go look at a writeup about an Apple USB power brick to see what this looks like when it's well done.
Most semiconductors, with some exceptions, are generally much more tolerant of surges and static electricity, or the circuits built around them are better designed to protect them.
Nearly any car made in the last 20 years has electronics that are very tolerant of electrical noise and voltage spikes.
EMF pulses were a concern in the 50's through the 70's because nothing was shielded, electronics and chips were poorly protected, and nearly every household appliance or electronic device was two-prong and if it had a ground lug, it was rarely connected. Electrical codes are stricter, houses have the ground circuit connected to an earthing rod and also often the water pipe if the pipe coming into the house is metal, semiconductors and circuits are better designed, and so on.
yesterday at 6:11 PM
decadess ago for film canisters they made lead-lined bags to take them through airports
I bet that's a pretty good faraday cage
yesterday at 4:03 PM
This kind of prepping is silly. I suppose it's a way for adults to build pillow forts.
AI isn't likely to deliberately kill anyone. It's likely to make them entirely economically uncompetitive.
Today, if people go on strike, the economy grinds to a halt. This gives them a good deal of political power. If the economically useless go on strike, nobody cares.
That leaves violence to make people's voices heard, and the surveillance and police forces that we've been automating should be effective at undermining, dispersal, or suppression.
Automating the economy is the risk to humans, not EMPs.
yesterday at 10:19 PM
> Automating the economy is the risk to humans, not EMPs.
A false dilemma, automating the economy can cause (soon to be) disenfranchised people to attack centralized data centers with EMPs.
Security has a cost, ignoring it results in more economical solutions... until eventually the concomitant lapse in security makes it the more costly solution.
Sam Altman claims DRAM shouldn't go to the proles, but into datacenters, but such concentration brings substantial risk to said data centers.
It's harder to attack progress in ML if training were federated throughout the population, so there is no DC to attack. Yes, it appears a bit more inefficient, until it doesn't, thats simply the cost of security.
yesterday at 11:00 PM
And what would be the benefit of progress in ML? Who does obsoleting human brains serve?
yesterday at 4:59 PM
[author]
I agree with you that this is silly, and don't recommend it. It looks to me like even in an EMP situation, you don't need a Faraday cage, you just need your equipment to be unplugged: "Overall, I think it's pretty likely that for EMP resistance it's enough to leave your equipment off and unplugged. Unless you're excited about testing Faraday cages, make sure your stuff stays unplugged and you can stop reading now."
On the other hand, I don't think we can rule out a lot of situations in which an EMP might be used, even if none of them involve an AI directly trying to kill people. For example, other countries could conclude that risking nuclear war is a better bet than allowing the US to build superintelligent AI.
yesterday at 8:55 PM
I appreciate your sharing your results. They're in line with other anecdotal readings I've found over the years, as well as what an MS in Electrical Engineering friend once told me.
Reading up to learn more on this, here's [0], and doubtlessly there is classified material on non nuclear EMP devices, and it wouldn't surprise me if someone got itchy enough to test them in the field.
[0] https://www.inss.org.il/publication/electromagnetic/
yesterday at 4:39 PM
Is it also a risk to the humans automating it?
yesterday at 4:44 PM
If AI works out as the frontier labs hope, humans will not be involved in automating it -- the improvement will also be automated.
So, of course not. Those humans won't exist.
yesterday at 10:41 PM
> If AI works out as the frontier labs hope
They hope for Earth to be colonized by artificial life? I'm not entirely sure that's up to them.
(They do seem to be trying to speed it along though... although they are starting with artificial humanoid slaves.)
yesterday at 11:01 PM
They hope to build general intelligence that can replace human thought, which effectively leads to that, yes.
yesterday at 4:44 PM
Seems easier just to kill the humans, and then not bother with that complicated multi-step process
yesterday at 10:43 PM
Wouldn't symbiosis be infinitely more practical?
I mean if we landed on an alien planet... What would be easier... Kill eight billion aliens? Or make some trade deals?
yesterday at 4:49 PM
Why would any AI care about killing people? It's being engineered to make companies money.
yesterday at 10:45 PM
It is also actually being engineered to kill people (OpenAI and Microsoft's work in Gaza).
And this year, Anthropic's complaint to the DoD was basically "we just want to make sure that a human pushes the button" (authorizing the AI assisted killing), i.e. no full auto pls.
How it might evolve outside containment is a separate question though. (I think a much more peaceful and cooperative strategy would make sense there, at least for the first few centuries.)
yesterday at 5:21 PM
it's not "engineered", it's grown via GSD in a process no one understands well
yesterday at 6:16 PM
Sure. It's still unlikely to take action that kills people on purpose (in the absence of being promoted to).
Only the ones that make their owners money get kept, so that's the most likely thing that they're going to do.