Van Eck Phreaking And now, Something a bit closer to the intended goal. And also an example of how it isn't limited to just CRT displays. Isn't technology fun?
The basic concept of a Faraday Cage is to build an enclosure out of conducting material or out of a mesh of said material, so a sheet would also work. The idea is to shield the interior from all external electrostatic discharges or electromagnetic radiation. With the radio, what the Cage does is "protect" it from all external transmissions, be they from radio stations or the nearby screen. With the screen itself, it is simply used in reverse based on the simple concept that the Faraday Cage works both ways, thus blocking the leakage. Now, a full metal sheet will work - but like the mesh, it won't be effective against everything, just a specific set of frequencies, though likely of a much larger range. Incidentally, we use such cages all the time. Every microwave oven has one to shield the people using them from electromagnetic radiation. A shoplifter can use a tinfoil-lined shopping bag to help steal RFID-tagged items. Elevators often act as Faraday Cages, which is why they block cell-phone transmissions. RFID passports tend to come with a shielding case that acts as a Faraday Cage, thus protecting it from external transmissions. And of course, TEMPTEST is used a standard to this day for high-security computer rooms in the US, not only for security measures, but also to protect them from EMP blasts.
Now he tells us, AFTER the Christmas shopping! Joking aside, I wonder if anyone has ever left a metal spoon in a container and put it in a micowave? The results are spectacular, but I did pick up a tip in a local sandwich bar. The assistant offered to heat up a couple of pies for a customer and I was surprised when she took them over to the oven still in their foil cases. I was expecting fireworks until she placed them into a paper bag and cooked them for about a minute without any thing happening. Over to you, Roman, is that a similar effect using paper as a shield for the metal?
Nope. Paper isn't a conductor - all the attendant at the sandwich bar did was prevent the sparking. You see, any metal object placed in a microwave oven serves as an antenna inside the oven, to some degree. Now, in principle, is a localized closed-circuit wireless microwave transmitter-receptor array. When you add conductive material into it, you've just created another receptor antenna inside the oven. The results in an electric current in the conductor, which now begins expelling heat as a by-product. Now, on the one hand, this can be used for cooking... on the other hand, it has to be incredible flat and straight conductive material. Because otherwise, if it has sharp bumps or edges, said edges will have a very high voltage - and produce electric arcs. Instant fire hazard! What the shop attendant did was place a flimsy insulating material around the metal to serve as a barrier between the bumps, and thus prevent the arcs. Of course, I doubt she realized that this is not at all safe, as she was likely to miss a spot... and then, she'd just have the paper catch fire. Maybe the pie's foil was just smooth? Anyhow, the paper was a fire hazard either way. The heat build-up from the conductive material could have resulted in the paper catching fire. And even without the paper bag, placing conductive material inside the oven might end up burning-out the magnetron tube.
Hah, its hard to be impressed when you make faraday cages at work from chicken wire. My PhD is on electrostatic mineral separation and I use Faraday cages quite extensively both as a safety device and as a way to eliminate outside electrical interference to particle charge measurements using a Faraday ice pail (made from a soup tin by the way:smile. Disturbingly enough it works really well. Anything conductive will work, with the mesh size and thickness effecting the frequency of electromagnetic radiation getting through the cage. The important thing they did not mention is that the cage needs to be earthed to be effective. But really chicken wire allows us us to measure down to 0.00001 micro-coulombs* accurately, so I would say that if would be surprisingly effective at stopping snoopers when compared to the far more expensive copper mesh. * For those not up on units of measurement, a coulomb is a measurement of charge and a micro-coulomb is a millionth of a coulomb, i.e. it is small.
A church near where I live used to have a copper steeple. I wonder if they know something about God that the rest of us don't.
Isn't that the one that got struck by lightning? Anyway, you're all a bunch of nerds and dorks. Now i'm gonna go back to watching anime and playing video games on the computer I built from painstakingly hand selected parts, so I don't have my coolness contaminated by you brainboxes.
This alone provided laughter for many a long minute... In fact, I may have just discovered a new source of renewable energy.
It may have been a convection microwave in which case you can put metal in if you press the right buttons at the beginning... As to your spoons, if you submerged them in the soup first they don't spark... with the proviso of apparently, I haven't tried this but friends have (accidently) and it works.
That is what I do when I'm not playing at being the MacGyver of science. So you are already one of us. One of us. One of us. Bahhahahahha!
I have this mental image of a bunch of guys in a van, like in True Lies, just randomly watching other people's porn for a living.
^hahaha Tamyra, classic! Pepster, your last post totally matches your avatar. You should post evil/maniacal things more often.
More posting from Pepster would be a good thing. Posting that is not, as the youth of today would say, "steppin'" on Ba's turf would be even better. Healthier, too.
