English DJ Claims Wi-Fi Allergy 515
path0$ writes "British Ex-DJ Steve Miller claims that his Wi-Fi allergy is making his life one big misery
, forcing him to live in an iron-clad home far from any neighbors. According to the article, more and more people are suffering from an allergy like his. The only positive side to this is that at least Miller didn't think of suing anybody yet, like these people did,
who claim to suffer from the same condition and were mentioned in a Slashdot article in 2008."
Re:Crazy people (Score:5, Informative)
Re:Crazy people (Score:5, Informative)
Personally, I'll start taking it seriously when at least one so-called sufferer can reliably report the appearance or disappearance of his symptoms in coordination with a randomly cycled emf source in a credible, double-blind experiment.
And He Can Profit! (Score:5, Informative)
A properly scientific proof of this would most likely qualify him for the JREF challenge. If he can physically detect relatively minor electromagnetic radiation on these frequencies, he could win himself a million dollars. http://www.randi.org/site/index.php/1m-challenge.html [randi.org]
Re:Easy to test (Score:5, Informative)
Quite right. People who claim to be "allergic" to modern technology invariably fail to prove it in properly designed double-blind scientific tests. In extreme cases, you find people who claim to be allergic to anything "artificial", be it synthetic fibers, plastics, electronic equipment, automobiles, or any one of a thousand other modern conveniences. Their complaints are real, but the root cause is psychological, not physical.
Some EHS (electro-hypersensitivity) sufferers go so far as to line their rooms and clothing with aluminum foil to supposedly "shield" themselves. In the most extreme cases, they move out into the country and adopt a 19th century lifestyle to completely divorce themselves from the modern world. Of course, they're still being exposed to EM radiation even in remote areas, as AM and shortwave radio transmissions span the globe, not to mention the EM radiation emitted by the sun. But once they believe they are safe from EM radiation, their symptoms abate.
Re:Crazy people (Score:5, Informative)
Some of the RFID units operate at extremely low frequencies - down in the kilohertz range. The lowest I've seen is in the 130-140 kHz range though.
These units usually use a LARGE coil as an antenna. There's a good chance the coil changes shape slightly with the duty cycle of the signal (lower than the carrier frequency) - this probably results in some audible energy coming from the security system coils. It may be such a low volume or at a frequency just outside of the normal human hearing range so that it can be "felt but not consciously heard". (This is a similar phenomenon to the well-known "GSM bleeps" - You can't hear 900 MHz or 1900 MHz RF, but you CAN hear when something in the environment rectifies it and low pass filters the signal envelope, because the GSM TDMA frame repeats at around 440 Hz.)
Similarly, CRT TVs often have horizontal refresh rates in the 15-16 kHz range, right in the upper end of the human hearing range. If the transformers in these TVs malfunctions slightly, they'll vibrate at this frequency. Really cheap/defective/failing monitors and TVs will make enough noise at hsync to be heard. I remember we used to have a monitor we had to junk because you couldn't use it for more than 20 minutes without developing a headache - it started squealing softly at hsync frequency.
Re:Easy to test (Score:5, Informative)
Yeah, let's do the math... (Score:4, Informative)
Exactly. Microwaves are allowed leak up to 5 mW/cm2 at 5 cm according to the FCC. Half that leakage (2.5mW/cm2), is almost exactly the same output as a typical wi-fi access point. Which means if he can stand next to the microwave while he nukes his burrito, he shouldn't have any issues with wi-fi.
So unless he's actually 802.11b/g sensitive, I call BS.
Re:Crazy people (Score:5, Informative)
Re:He can probably earn $1M bucks if legit... (Score:4, Informative)
From the Foundation's FAQ on the challenge ( http://www.randi.org/site/index.php/component/content/article/37-static/254-jref-challenge-faq.html [randi.org] ):
Many people have already undergone preliminary testing by the Foundation. Their claims have been deemed "paranormal." None of them succeeded in proving the abilities they claimed. I don't have the source handy, but I'm pretty sure that Randi himself has stated in the past that this sort of EM sensitivity would qualify.
Re:Test This Claim: (Score:5, Informative)
This submission was posted by sampenzus which means it's just more idle crap polluting the front page.
Re:Crazy people (Score:4, Informative)
Sounds like any properly blinded experiment.
The MSG episode was almost on par with a MythBusters experiment. One group got MSG (all on one side of the room), one group didn't (other side of the room). After eating they asked for food enjoyment and symptoms, then who thought the food had MSG. Better studies have presented the same result with more precise conditions.
Re:Crazy people (Score:5, Informative)
In 2005, a systematic review looked at the results of 31 experiments testing the role of electromagnetic fields in causing ES. Each of these experiments exposed people who reported electromagnetic hypersensitivity to genuine and sham electromagnetic fields under single- or double-blind conditions.[1] The review concluded that:
"The symptoms described by 'electromagnetic hypersensitivity' sufferers can be severe and are sometimes disabling. However, it has proved difficult to show under blind conditions that exposure to electromagnetic fields can trigger these symptoms. This suggests that 'electromagnetic hypersensitivity' is unrelated to the presence of electromagnetic fields, although more research into this phenomenon is required."
Seven studies were found which did report an association, while 24 could not find any association with electromagnetic fields. However, of the seven positive studies, two could not be replicated even by the original authors, three had serious methodological shortcomings, and the final two presented contradictory results. Since then, several more double-blind experiments have been published, each of which has suggested that people who report electromagnetic hypersensitivity are unable to detect the presence of electromagnetic fields and are as likely to report ill health following a sham exposure, as they are following exposure to genuine electromagnetic fields.
Re:Crazy people (Score:3, Informative)
Which is part of the point, he's story is bunk. WiFi isn't bothering him, any more than all the other electronic crap he uses is.
Of course your 900mhz equipment has nice side bands at 1.8ghz and 2.7ghz (and every other multiple of 900mhz as well), so you can't exactly rule it out.
The reality of course is that he's just crazy, but my point is that just because you're wireless gear works at its intended frequency of 900mhz, doesn't mean that both the transmitter and reciever are only emitting in the 900mhz range. They are BOTH emitting radiation at multiple frequencies, just generally at a very low (hopefully) power output as to not bother anything else. Harmonics are a bitch, good filtering helps but doesnt' prevent the problem.
Re:Crazy people (Score:3, Informative)
Detectors almost always emit as well, they have to generate their own signals to enter a PLL in order to detect other signals.
The idea however is that the detector will emit far less on its operating frequency and the harmonics will be a lot lower.
Re:Crazy people (Score:4, Informative)
Can you block the transmission of higher sideband frequencies by using a properly tuned crystal or one that can't possibly oscillate at those higher sideband frequencies?
Harmonics are caused by nonlinearities in the oscillator and the amplifier; they are not "oscillations" as such, but components of the spectrum formed by imperfections in transistors (or even vacuum tubes.) Harmonics can be greatly reduced in a single-frequency system by just using an LC filter (several configurations exist) and that also helps with antenna matching. Wideband systems require low-pass filters, and that is less efficient. I think a wireless microphone or a guitar would use just a single FM channel with undetectably low power. The ERP [wikipedia.org] at 900 MHz could be about 1 mW (say, 0 dBm,) and the second harmonic could be *easily* suppressed down to 1 microwatt (-30 dBm). Typically RF equipment suppresses harmonics by 40 or 50 dB. Elecraft K3 [elecraft.com], for example, guarantees at least 50 dB suppression of harmonics - and that with several bands that are not that narrow.
Re:Found a corroborating study on the net (Score:3, Informative)