Chicken Wire
What I did was to get the finest mesh chicken wire I could get. And then use 2 layers, overlapping them so that the second layer's wires bisected the holes from the first one. I have used a copper mesh screened room before.
My calculation gave me a 30db reduction up to about 2 GHz with a rise to no protection above 10GHz. Cosmic rays I have to live with.
What I did was to get the finest mesh chicken wire I could get. And then use 2 layers, overlapping them so that the second layer's wires bisected the holes from the first one. I have used a copper mesh screened room before.
My calculation gave me a 30db reduction up to about 2 GHz with a rise to no protection above 10GHz. Cosmic rays I have to live with.
You could try to get a sample of Magnetic paint and see how much it cuts down the field from the dect phone, also window tint will bock about as well as the antistatic bags do.
You might find lessemf.com handy for ideas.
Hope this helps
Regards
James
You might find lessemf.com handy for ideas.
Hope this helps
Regards
James
Sorry, a bit off topic.
When a handphone is near an audio amplifier+loudspeaker, when there is an incoming call, the loudspeaker reproduces that "teet..teet..teet..teet..teet..teet..teet" sound.
What is the mechanism that this handphone signal entering the amplifier/speaker system?
Is it possible to eliminate this handphone signal sound when a handphone is placed near a sound system? How? Shielding with metal, RF paper, etc seems not helping at all.
When a handphone is near an audio amplifier+loudspeaker, when there is an incoming call, the loudspeaker reproduces that "teet..teet..teet..teet..teet..teet..teet" sound.
What is the mechanism that this handphone signal entering the amplifier/speaker system?
Is it possible to eliminate this handphone signal sound when a handphone is placed near a sound system? How? Shielding with metal, RF paper, etc seems not helping at all.
I_F, i don't live in the north of France (remember Asterix?)
Thanks Dm fraser. I thought also on a screen of mesh work. In fact a fine metal anti-insect mesh could do perfect. Magnetic paint is rather expensive. When i move into a new house i will sure consider it on all walls, cheap alufoil with small pitts to let it dry better after glueing.
The "bede-beep" is from interference of modulated RF in the electronic, my tube gear is less sensitive to it, car radio very sensitive.
Thanks Dm fraser. I thought also on a screen of mesh work. In fact a fine metal anti-insect mesh could do perfect. Magnetic paint is rather expensive. When i move into a new house i will sure consider it on all walls, cheap alufoil with small pitts to let it dry better after glueing.
The "bede-beep" is from interference of modulated RF in the electronic, my tube gear is less sensitive to it, car radio very sensitive.
The telephone operates at a very high frequency, probably 2MHz or higher.lumanauw said:
But it sends information in bursts or packets, one type of phone sends the packets at a 217Hz rate.
The packets demodulate in your equipment and cause short DC off-sets.
The Maxim IC Co. has a seminar on the web that covers this problem.
I and problably my youngest doughter, are one of the 3% of the human population who is sensitive to EM radiation.
Take an half a hour for this: http://next-up.org/divers/BBConePanoramaWiFiWarningSignal22052007HD.php
Take an half a hour for this: http://next-up.org/divers/BBConePanoramaWiFiWarningSignal22052007HD.php
I think that you are far more susceptible to the suggestion of the possibility of health effects than you are to RF radiation.
You want to know the impact of having wifi in the classroom? Go to a 3rd world country that doesn't have it and see the quality of education the kiddies are getting. THAT is impact that can be seen and measured.
Access to the internet is an extremely valuable resource.
There have been similar scares about fluorescent lighting, synthetic materials (plastics in carpets, etc.), fluoridation of water and every other thing you can imagine. The only two that have ever been shown to actually cause problems are lead in paint and asbestos insulation.
The media loves to keep people frightened because it sells commercials and papers. It also helps politicians who keep peoples' attention on nonsense that has nothing to do with running a country. If you can get them to vote based on stupid stuff like antenna towers, or whether someone is porking someone other than his wife, why risk having to talk about important issues like foreign policy, wars, corruption, etc.
I suggest you make the Red Hot Chili Peppers "Fight Like a Brave" your theme song. Play it every morning when you wake up and face the world with a more positive attitude.
I_F
You want to know the impact of having wifi in the classroom? Go to a 3rd world country that doesn't have it and see the quality of education the kiddies are getting. THAT is impact that can be seen and measured.
Access to the internet is an extremely valuable resource.
There have been similar scares about fluorescent lighting, synthetic materials (plastics in carpets, etc.), fluoridation of water and every other thing you can imagine. The only two that have ever been shown to actually cause problems are lead in paint and asbestos insulation.
The media loves to keep people frightened because it sells commercials and papers. It also helps politicians who keep peoples' attention on nonsense that has nothing to do with running a country. If you can get them to vote based on stupid stuff like antenna towers, or whether someone is porking someone other than his wife, why risk having to talk about important issues like foreign policy, wars, corruption, etc.
I suggest you make the Red Hot Chili Peppers "Fight Like a Brave" your theme song. Play it every morning when you wake up and face the world with a more positive attitude.
I_F
I like RHCP, have Californication but played it only 2 times, that album is of that quality it could be recorded with a laptop soundcard.
Imo 3rd world kids would be helped more with a western world discarded Apple G3 with OS 9 or an old X86 P3 with Edubuntu, cost-effective and virus-free, hard wired LAN reduces costs even more.
Imo 3rd world kids would be helped more with a western world discarded Apple G3 with OS 9 or an old X86 P3 with Edubuntu, cost-effective and virus-free, hard wired LAN reduces costs even more.
I_F, i have been thinking about your comments, but the investigations tell a lot nowadays. I will simply start with some screening tests and see what happens.
btw i just am playing a DVD, Depeche Mode, the song "walking in my shoes" more my personal song on this very moment. (I think the neighbour must hear it too by now
)
btw i just am playing a DVD, Depeche Mode, the song "walking in my shoes" more my personal song on this very moment. (I think the neighbour must hear it too by now
)
Did in meantime some screening.
*Behind my bed is a decoration panel to neighbours wall, shielded it with a thin metalised isolation blanket: 50% reduction of EM (I am not sure what dB-reduction that is) but new reading is just sub recommended "night" value of 6 mV/m.
*Under the matrass of my 6 yo doughter, sleeping 2 metres oblique above the neighbours dect, i have putted a metalised car-window freezing blanket. Before-after readings: 50mV/m @ head position, after: 7 mV/m. Btw discovered just right behind the screen readings are lower, with more proximity from screen the readings increase again. It look like the EM radiation can bend some around the screen, or the whole screen starts to emit too. Grounding of screen helps some to flow some extra energy away (I grab the foil with wet fingers)
Results with my doughter so far after a week is: She is nicer in the morning, more cooperative with the usual morning rituals of washing/dressing/toothbrushing. At night when i look at her she often teeth grinded, so loud i could sometimes hear it in the other room at night. Now the bruxism is allmost gone, and it's clearly obvious she sleeps a lot more relaxed now. Btw this is no coincidence imo, it's the 2nd time i discovered the bruxism fact, about 1 year ago my neighbour removed for a week or so his dect after i asked for. A reduction in teeth-grinding as result. But he wants to connect 4 dects on one base station, so reinstalled the dect again. Also my wife reported a reduction in bruxism, she has (fortunately?) a more common-sense thinking on the whole EM radiation matter. But on the other hand: she works in an hospital on the top floor right under GSM-UMTS antenna's, in that area she suffers often from sight problems and a "warm" headache, with a colleage too.
To do list:
*A metalised blanket of 2 layers will be fit behind the large poster, silk printout is delivered this week, busy with a frame at the moment. Will try magnetic paint soon. The dect radiates in main room with huge readouts, eg 500 to 1000 mV/m, and my 6 yo doughter eats there right on that spot.
*A metalised blanket will be hanged behind large book cabinet wherein the stereo equipment is, it is right between my favorite chair and the 24/7 radiating WIFI gear of neighbour. Well, a saying in Holland is: Slam two fly's with one hit: Less EM radiation in my room, and the stereo is better EM screened.
*Behind my bed is a decoration panel to neighbours wall, shielded it with a thin metalised isolation blanket: 50% reduction of EM (I am not sure what dB-reduction that is) but new reading is just sub recommended "night" value of 6 mV/m.
*Under the matrass of my 6 yo doughter, sleeping 2 metres oblique above the neighbours dect, i have putted a metalised car-window freezing blanket. Before-after readings: 50mV/m @ head position, after: 7 mV/m. Btw discovered just right behind the screen readings are lower, with more proximity from screen the readings increase again. It look like the EM radiation can bend some around the screen, or the whole screen starts to emit too. Grounding of screen helps some to flow some extra energy away (I grab the foil with wet fingers)
Results with my doughter so far after a week is: She is nicer in the morning, more cooperative with the usual morning rituals of washing/dressing/toothbrushing. At night when i look at her she often teeth grinded, so loud i could sometimes hear it in the other room at night. Now the bruxism is allmost gone, and it's clearly obvious she sleeps a lot more relaxed now. Btw this is no coincidence imo, it's the 2nd time i discovered the bruxism fact, about 1 year ago my neighbour removed for a week or so his dect after i asked for. A reduction in teeth-grinding as result. But he wants to connect 4 dects on one base station, so reinstalled the dect again. Also my wife reported a reduction in bruxism, she has (fortunately?) a more common-sense thinking on the whole EM radiation matter. But on the other hand: she works in an hospital on the top floor right under GSM-UMTS antenna's, in that area she suffers often from sight problems and a "warm" headache, with a colleage too.
To do list:
*A metalised blanket of 2 layers will be fit behind the large poster, silk printout is delivered this week, busy with a frame at the moment. Will try magnetic paint soon. The dect radiates in main room with huge readouts, eg 500 to 1000 mV/m, and my 6 yo doughter eats there right on that spot.
*A metalised blanket will be hanged behind large book cabinet wherein the stereo equipment is, it is right between my favorite chair and the 24/7 radiating WIFI gear of neighbour. Well, a saying in Holland is: Slam two fly's with one hit: Less EM radiation in my room, and the stereo is better EM screened.
tubee said:
The reduced grinding of the teeth, if a real phenomenon, is more likely due to the reduced stress levels in your home. The reduced stress level is due to your reduced stress because by hanging up sheets of foil you feel like you are getting "the problem" under control. Once you have "solved" this problem, you will probably find another to obsess over and stress levels will return to baseline.
tubee said:
Now you are looking for evidence to support your view and ignoring evidence that does not. This is an error made by a lot of people. It is the basis for junk-sciences such as numerology and astrology. Look for papers published by David Dunning in psychological journals. He can tell you all about such things.
I_F
Interesting read:
http://home.att.net/~profmulder/Incompetence.htm
So Einstein was not competent, his formula's are ever since corrected a few times by others, and they are then not competent either.
http://home.att.net/~profmulder/Incompetence.htm
So Einstein was not competent, his formula's are ever since corrected a few times by others, and they are then not competent either.
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