[deleted]
Testing Phone-Sized Faraday Bags
111–120 of 205 posts
Re: Testing Phone-Sized Faraday Bags
#112> While the cookie tin performed much better than the mylar bags, and could provide a modicum of useful attenuation under some circumstances, it was not sufficient to provide meaningful assurance of signal isolation at any frequency. However, it was unique among the containers tested in providing tasty snacks during measurements Back in the day working for Symbian I used to regularly have to run a load of automated B…
When I was in jail I had a cellie who imported drugs from China. They were always shipped inside defunct microwave ovens. I wondered if it was just because it looked like a harmless kitchen appliance or because the microwave provided shielding from an x-ray scan?
Re: Testing Phone-Sized Faraday Bags
#113I 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…
I think the issue is then you have to wait until you are already inside the hotel to use those shakers, which as others have said don’t actually exist in most hotels, and at that point you have been tracked to your exact location. Then it would be trivial to surveil you with other methods without needing your phone.
Re: Testing Phone-Sized Faraday Bags
#114That was really interesting. I can’t believe how poorly the metal tin box did compared to real faraday pouches.
The metal tin box will have had varnish and paint on it's surfaces. That means at the junction between the tin and the lid (and maybe other joins), there isn't an electrical connection all along. Having two metal surfaces next to eachother, but with an insulator in between, acts like a 'choke flange'[1]. However, they only work at one specific frequency - at all other frequencies they will leak either a little signal…
What I hear from you is that soldering a wire connection between the tin can and its lid should improve it's function as a Faraday cage?
Re: Testing Phone-Sized Faraday Bags
#115Where I live, all I have to do to block 4G is to stop standing in the far corner of the yard.
left arm not in the air and both feet on the ground seems to get rid of the 4g signal for me. I do miss the old days of tuning the rabbit ears on top of the tv for best reception.
Try this trick... with your feet in the air and your head on the ground, spin it.
Did you get an earworm? I sure did.
Re: Testing Phone-Sized Faraday Bags
#116This 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…
I agree that the free market is easily gamed and therefore I really am glad to be living in a country with relatively strong consumer protection laws. I buy online, I can return within two weeks no question asked. It breaks within two years - I return it. Either I get a repaired one or a new one or my money back. There are few exceptions but mostly it makes shopping quite secure. Yes. There are bad actors. Yes people…
What country do you live in?
Re: Testing Phone-Sized Faraday Bags
#117Earlier quoted context omitted.
I assume for the same reason you ground your home, building up charges is a great way for Bad Things to happen.
Why would a phone pouch/box build up great charge? You don't ground your home because of charge buildup either - grounding is there to decrease the chance a thunderbolt will run through precious things, like house walls, people, electric wiring etc.
Grounding and bonding is done for many safety reasons. Reducing stray voltage is certainly one of them:
https://www.mikeholt.com/technical-stray-voltage-newsletter-...
Re: Testing Phone-Sized Faraday Bags
#118I 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…
It is hard to believe this would perform better than a Lazzaroni tin. And I don't recall ever finding one of these things in a hotel room, even in Europe.
I imagine I've seen them now and then but they're hardly common. I'm grateful when I get real glassware.
Re: Testing Phone-Sized Faraday Bags
#119Electronic 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...
Re: Testing Phone-Sized Faraday Bags
#120Earlier quoted context omitted.
> The average hotel room in any medium/large hotel chain probably includes a shaker as a standard item as part of the minibar. Maybe the hotels you stay in, Bond, James Bond.
I admit the vast majority of my experience with hotels consists of a single repeated data point: the staff[1] suite(s) we shared in the Hilton attached to the SJ convention center. They always had glasses/shaker/etc. You could probably ask for a shaker from roomservice or the hotel bar, if necessary. [1] If you registered for FanimeCon 2000-2011, the weird software you had to use was my fault...
Hilton is a tiny bit more fancy than the average.