Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Testing Phone-Sized Faraday Bags

mattblaze.org

Post reply on HN
Print view View original

181–190 of 205 posts

Re: Testing Phone-Sized Faraday Bags

#181

Post by joshspankit »

thatguy0900 wrote: post #142
throw10920 wrote: post #137

Earlier quoted context omitted.

I'd like to describe a complementary problem to yours - that it's very difficult or impossible to find out others' experiences with a product's quality, durability, and performance. That is - the complement to the problem of "it's hard to determine if some products work" is "it's hard to find other users' experiences with the product". Amazon reviews are completely worthless, but very few other platforms have anywher…

Maybe products have just reached a point of being overall just cheap enough and just good enough that consumers largely don't need to care about reviews? You talk about effort to buy a good car, maybe the average car is just good enough now. I wonder what percentage of younger people have bought an actual lemon that would cause them to be cautious.

I begrudgingly feel that things being good enough is they main why. And I say begrudgingly because it means less and less are caring about excellence while more and more becomes trash.

Fuelling it is that there are people in the “I want my In our current society people with funds and not time see a clear ROI for shooting for 80% success because it means not having to spend time thinking or sorting out logistics.

Re: Testing Phone-Sized Faraday Bags

#182

Post by joshspankit »

gangstead wrote: post #158
theshrike79 wrote: post #143

Earlier quoted context omitted.

Linus Tech Tips is attempting something in this field: https://www.youtube.com/watch?v=pt3-6BsWlPk tl;dw They're building a setup where they can test a bunch of computer equipment with standardised tests (built by them) in a standardised environment (also built by themselves).

Sounds like what Consumer Reports does across various fields.

It’s all well and good until you get enough clout that a bad actor offers you a very large cheque to rig the game.

Re: Testing Phone-Sized Faraday Bags

#183

Post by joshspankit »

rocqua wrote: post #75
causi wrote: post #26

Earlier quoted context omitted.

What's the physics behind being able to make a container light-tight with a couple of right angle corners yet radio waves seem to leak out like water?

Also, 20-30 Db of attenuation for light is already quite a lot. Whilst for a radio signal it is still very conceivable that 30Db of attenuation still allows for a signal to be received. Our eyes simply aren't very sensitive instruments. And the visible part of the spectrum is uncharacteristically full of 'noise', so it makes some sense that our eyes don't need to detect any signals that are too far below the noise-fl…

As well: because of reed solomon a modern digital signal can be reconstructed from flickers and fragments of the radio waves

Re: Testing Phone-Sized Faraday Bags

#184

Post by mfkp »

SamuelAdams wrote: post #57

This is a super cool blog post. However I think it alludes to a much larger problem. For many products today, it’s very difficult or impossible for most people to verify the product works. For a network switch, there are free and open source tools like iPerf to test and verify speeds are as advertised. For a faraday box, you have to go through all these steps (and knowledge learned) just to be able to test these. Wha…

> What about for vitamins, or pet food

https://www.consumerlab.com/ does a great job testing vitamins and other various things put in or on your body. Well worth the subscription price.

Re: Testing Phone-Sized Faraday Bags

#185

Post by effie »

joshspankit wrote: post #183
rocqua wrote: post #75

Earlier quoted context omitted.

Also, 20-30 Db of attenuation for light is already quite a lot. Whilst for a radio signal it is still very conceivable that 30Db of attenuation still allows for a signal to be received. Our eyes simply aren't very sensitive instruments. And the visible part of the spectrum is uncharacteristically full of 'noise', so it makes some sense that our eyes don't need to detect any signals that are too far below the noise-fl…

As well: because of reed solomon a modern digital signal can be reconstructed from flickers and fragments of the radio waves

What does this mean? A fragment of a radio wave is still a radio wave and can carry information irrespective of whether reed solomon or other encoding is used, no?

Re: Testing Phone-Sized Faraday Bags

#186

Post by effie »

gdelfino01 wrote: post #119

Electronic voting machines should be put inside Faraday cages too. Specially now that communication chips have been found hidden in some of their motherboards. https://letsfixstuff.org/2021/04/modem-chips-embedded-in-vot...

Electronic voting is much easier to subvert than boring old paper-tech voting. It should be rejected for important elections.

Re: Testing Phone-Sized Faraday Bags

#187

Post by effie »

pseudolus wrote: post #68

Bit of an aside but the ineffectiveness of tin foil hats to prevent government intrusion into our minds has been known for some time :) http://web.archive.org/web/20100708230258/http://people.csai...

Btw, to prevent abovementioned government/other powerful groups intrusions into our minds, I recommend to stop consuming MSM. That's the most powerful tool of intrusion/control they have.

Re: Testing Phone-Sized Faraday Bags

#188

Post by effie »

fsflover wrote: post #93
323 wrote: post #71

Earlier quoted context omitted.

But you need to trust that they are actually working, and that the device was not intercepted and modified en route.

They have the schematics [0,1] for these devices and even X-rays [1] for Librem 5. Also, anti-interdiction services for the latter [2]. [0] https://wiki.pine64.org/index.php/PinePhone#PinePhone_board_... [1] https://source.puri.sm/Librem5/community-wiki/-/wikis/Freque... [2] https://puri.sm/posts/anti-interdiction-services/

Isn't this rather a security theater for the more naive prospective buyers? Even if the device is verified to comply with high-level schematics, it still may not comply on the micro-level. There is the problem with all modem chips being able to access/control phone memory and being potentially controllable by the mobile network operator. How are we going to verify this vulnerability has been removed?

Re: Testing Phone-Sized Faraday Bags

#189

Post by lmilcin »

That red plastic "mylar bag" isn't what should have been tested.

Red plastic == electrostatic dissipative. It is not good at conducting electricity -- it is still very good insulator. It just has ability to dissipate electric charge fast enough so that it will not accumulate in normal use.

What you have wanted to check is a clear bag with metalized layer (which is silver or gray looking). It should, per my understanding, act as much better faraday cage than an electrostatic dissipative bag. And I would be really interested in seeing that measurement.

Re: Testing Phone-Sized Faraday Bags

#190

Post by Johnythree »

kurthr wrote: post #163
pdkl95 wrote: post #15

I really like Snowden's recommended Faraday cage for phones or other devices of similar size: two drink-shaker cups[1]. Drink shakers are cheap and widely available. The average hotel room in any medium/large hotel chain probably includes a shaker as a standard item as part of the minibar. The simple two-cup style (as seen in [1]) is preferred over the fancier "strainer top" style because you can press the two cups t…

If you're interested in simple cages similar in effectiveness to the EDEC Window Pouch (they drop off above 3GHz)... try a Microwave Oven. They are highly available, reasonably convenient and well designed, with pretty good quality control. You can even still see your phone inside has zero bars. I do, however, recommend unplugging the microwave (or even cutting the power cord) as a fire would likely result from cooki…

The door seals in most microwave ovens consist of tuned slots (eg half-wave stubs) to prevent the RF escaping. These are ineffective at frequencies other than 2.4Ghz.

The reason for the tuned slots is that it's basically impossible to make a conventional metal joint which will seal sufficiently well.

Post reply on HN