A father accidentally shut down his town's whole internet in an effort to limit his kids' screentime
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There are four general requirements for a Faraday cage: 1. The cage must be complete - no holes in the ceiling, floor, doors, or windows. 2. The cage must be made of electrically-conductive material 3. The distance between the cage's "bars" must be smaller than (some fraction of) the shortest wavelength that you wish to block 4. The faraday cage should be grounded If you wish to stop everything up to Wi-Fi 6E (6GHz band), you will need a separation between "bars" of no more than 3x108/6x109 = 5x10-2 meters. A few layers of metal mosquito netting covering the floor, walls, ceiling, doors, and windows should create a decent Faraday cage for Wi-Fi and cell-phone signals.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
OR you could just take the device away from the child.
I’ve given up trying to be calm. However, I am open to feeling slightly less agitated.
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That is awesome, give that man a prize!
"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment "Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst "I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle
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OR you could just take the device away from the child.
I’ve given up trying to be calm. However, I am open to feeling slightly less agitated.
I was referring to trønderen's idea of building a Farady cage around his TV room. I agree that for children the best solution is to take away their phones when they aren't supposed to be using them.* (*) Assuming that the kids aren't bigger and stronger than you are...
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
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There are four general requirements for a Faraday cage: 1. The cage must be complete - no holes in the ceiling, floor, doors, or windows. 2. The cage must be made of electrically-conductive material 3. The distance between the cage's "bars" must be smaller than (some fraction of) the shortest wavelength that you wish to block 4. The faraday cage should be grounded If you wish to stop everything up to Wi-Fi 6E (6GHz band), you will need a separation between "bars" of no more than 3x108/6x109 = 5x10-2 meters. A few layers of metal mosquito netting covering the floor, walls, ceiling, doors, and windows should create a decent Faraday cage for Wi-Fi and cell-phone signals.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
The elevator "cage", steel plates all over, definitely satisfies the first three criteria. It may not have been perfectly grounded, but I would expect it to hang in a steel chain with metallic contact to the walls, and I would expect the chain to have metallic contact to parts of the motor that is grounded. My expectations may be wrong. The criteria are fine and clearly stated. Yet the realization seems to be more difficult than one might expect from the clearness of the criteria.
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I've been considering a similar civil disobedience action, more at the "prank" level: I live at the outer coverage edge of the Frankfurt, Germany, radio clock DCF77 signal. If weather/atmospheric conditions are unfavorable, my 1st floor DCF77 clock may not be able to pick up the signal (once it was a day late before picking up the Daylight Savings Time change), while the 2nd floor clock usually synchronizes without problems. Yet, it shouldn't take much power to drown out the Frankfurt signal. '77' in 'DCF77' refers to the frequency: 77.5 kHz. For a radio signal, that is very low. It is actually so low that you can generate it with any sound card handling 192 kHz sampling rate, and a lot of them do. A lot of modern stereo amps accept a 192 kHz PCM signal on the digital input, and can generate an analog signal up to 100 kHz on the speaker outputs. The encoding is rather primitive (Wikipedia: DCF77[^]) - I frequently jokingly refer to it as "Morse Mark II". So if I make a small program for my PC, generating signals for all the DCF77 alarm clocks in the neighborhood that "It is six o'clock, time to get up!" a couple hours early ... My 50 W/channel amp, with an antenna connected to the speaker outlets would easily drown the Frankfurt DCF77 signal. There is supposed to be a clock signal at 77.5 kHz. I think it would take the authorities a long time to discover that the signal is stronger than it "should be", and carrying an incorrect time value. Probably, the DCF77 alarm clock owners would blame their clocks, not the radio signal. I haven't dared to realize it, an I probably never will. Nevertheless, playing with the idea is sort of fun :-) (In other parts of the world, there are similar but not identical clock radio services, some at even lower frequencies. The data format may be different. If you pick up this idea to realize it in your district, let us hear about it!) This idea is somewhat inspired by a couple of "community FM radio stations" long time ago, when Norway had a state monopoly on radio broadcasts. Usually, there were no broadcasts between midnight and 6 a.m. So some pirate radios picked up the state channel, retransmitting it locally on a different frequency, usually with a much higher signal level. So lots of listeners tuned their receivers to that frequency, giving the pirate radio a lot of listeners for their midnight-to-6am transmissions. At daytime, the authoriti
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I was referring to trønderen's idea of building a Farady cage around his TV room. I agree that for children the best solution is to take away their phones when they aren't supposed to be using them.* (*) Assuming that the kids aren't bigger and stronger than you are...
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
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The elevator "cage", steel plates all over, definitely satisfies the first three criteria. It may not have been perfectly grounded, but I would expect it to hang in a steel chain with metallic contact to the walls, and I would expect the chain to have metallic contact to parts of the motor that is grounded. My expectations may be wrong. The criteria are fine and clearly stated. Yet the realization seems to be more difficult than one might expect from the clearness of the criteria.
I think you'll find that there is more plastic in those elevator cages than you think. For example, anodized plastic can look very much like stainless steel, but is much cheaper. Again, just my theory. :)
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
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I think you'll find that there is more plastic in those elevator cages than you think. For example, anodized plastic can look very much like stainless steel, but is much cheaper. Again, just my theory. :)
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
Plastic doesn't go clunck! in the same was as steel. Plastic doesn't fee cold the same way that steel does. I know the feeling of steel as opposed to anodized plastic! OK, I'll accept your belief that if your guidelines are followed, a Faraday cage works as my schoolbooks said they will. You think they will. I'll let you believe so. So I will have to ask someone else why our elevator cage - and numerous other attempts of shielding a room / cage from electromagnetic radiation - fail in creating an efficient Faraday cage. Your principles are obviously fine - as if quoted from textbooks I read long ago. But they fail do explain why it doesn't work in practice, in lots of specific cases. If you think it really is as simple as you seem to suggest, then you might make a fortune on offering your services to this French father, to theaters, movie theaters and concert halls.
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Plastic doesn't go clunck! in the same was as steel. Plastic doesn't fee cold the same way that steel does. I know the feeling of steel as opposed to anodized plastic! OK, I'll accept your belief that if your guidelines are followed, a Faraday cage works as my schoolbooks said they will. You think they will. I'll let you believe so. So I will have to ask someone else why our elevator cage - and numerous other attempts of shielding a room / cage from electromagnetic radiation - fail in creating an efficient Faraday cage. Your principles are obviously fine - as if quoted from textbooks I read long ago. But they fail do explain why it doesn't work in practice, in lots of specific cases. If you think it really is as simple as you seem to suggest, then you might make a fortune on offering your services to this French father, to theaters, movie theaters and concert halls.
trønderen wrote:
So I will have to ask someone else why our elevator cage - and numerous other attempts of shielding a room / cage from electromagnetic radiation - fail in creating an efficient Faraday cage. Your principles are obviously fine - as if quoted from textbooks I read long ago. But they fail do explain why it doesn't work in practice, in lots of specific cases.
I give up. Perhaps you can write to the manufacturers of the elevator, and ask them about the design of their elevator cages. All I know is that the physics are correct, and if the Faraday cage is properly designed - it will work.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
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I've been considering a similar civil disobedience action, more at the "prank" level: I live at the outer coverage edge of the Frankfurt, Germany, radio clock DCF77 signal. If weather/atmospheric conditions are unfavorable, my 1st floor DCF77 clock may not be able to pick up the signal (once it was a day late before picking up the Daylight Savings Time change), while the 2nd floor clock usually synchronizes without problems. Yet, it shouldn't take much power to drown out the Frankfurt signal. '77' in 'DCF77' refers to the frequency: 77.5 kHz. For a radio signal, that is very low. It is actually so low that you can generate it with any sound card handling 192 kHz sampling rate, and a lot of them do. A lot of modern stereo amps accept a 192 kHz PCM signal on the digital input, and can generate an analog signal up to 100 kHz on the speaker outputs. The encoding is rather primitive (Wikipedia: DCF77[^]) - I frequently jokingly refer to it as "Morse Mark II". So if I make a small program for my PC, generating signals for all the DCF77 alarm clocks in the neighborhood that "It is six o'clock, time to get up!" a couple hours early ... My 50 W/channel amp, with an antenna connected to the speaker outlets would easily drown the Frankfurt DCF77 signal. There is supposed to be a clock signal at 77.5 kHz. I think it would take the authorities a long time to discover that the signal is stronger than it "should be", and carrying an incorrect time value. Probably, the DCF77 alarm clock owners would blame their clocks, not the radio signal. I haven't dared to realize it, an I probably never will. Nevertheless, playing with the idea is sort of fun :-) (In other parts of the world, there are similar but not identical clock radio services, some at even lower frequencies. The data format may be different. If you pick up this idea to realize it in your district, let us hear about it!) This idea is somewhat inspired by a couple of "community FM radio stations" long time ago, when Norway had a state monopoly on radio broadcasts. Usually, there were no broadcasts between midnight and 6 a.m. So some pirate radios picked up the state channel, retransmitting it locally on a different frequency, usually with a much higher signal level. So lots of listeners tuned their receivers to that frequency, giving the pirate radio a lot of listeners for their midnight-to-6am transmissions. At daytime, the authoriti
I know nothing about your countries telecom enforcement agencies; but suspect they'd have as negative a reaction as the French did in the linked story or the US FCC has in various other cases of unauthorized broadcasting I've read about over the years.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, weighing all things in the balance of reason? Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful? --Zachris Topelius
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trønderen wrote:
So I will have to ask someone else why our elevator cage - and numerous other attempts of shielding a room / cage from electromagnetic radiation - fail in creating an efficient Faraday cage. Your principles are obviously fine - as if quoted from textbooks I read long ago. But they fail do explain why it doesn't work in practice, in lots of specific cases.
I give up. Perhaps you can write to the manufacturers of the elevator, and ask them about the design of their elevator cages. All I know is that the physics are correct, and if the Faraday cage is properly designed - it will work.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
Thing is, you simply repeat what the textbook says, with no indication of where, why, how the straightforward approach fails (beyond repeating the textbook). If I try building a Faraday cage, and it doesn't work well, I guess you would quote the textbook again. An expert would go searching for well known pitfalls, and probably find some. I'd love to know of those pitfalls in advance.
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I know nothing about your countries telecom enforcement agencies; but suspect they'd have as negative a reaction as the French did in the linked story or the US FCC has in various other cases of unauthorized broadcasting I've read about over the years.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, weighing all things in the balance of reason? Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful? --Zachris Topelius