Via Skeptico and one of his readers I became familiar with a new scare.
Now, I know that some people think that they are electrosensitive, others think that cell phone use leads to cancer. This question was asking about s specific wireless technology called DECT and whether or not it could be dangerous. He got turned on to this worry due to a number of articles about it. Like this one and this one. One thing to point out.. every single article I can post eventually points back to this single article on the subject. Shall we raise the nonsense flag now? No, I think we can delve into it a bit.
Before we start, I think we should go over radiation and radiowaves. There is so much equivocation out there about various terms its no wonder people get freaked out.
Radiation: When we talk about radiation we are talking about the projection of energy from a source, which travels through some sort of medium (it could be air, or vacuum, or camel poo) which eventually get absorbed or reflected by some other object (which is usually referred to as a body, initiating even more equivocation, it doesn't mean human body). This energy could be in the form of sound waves, water ripples on a pond, light, gamma rays. These are all radiation. Clearly we do not have to worry about most of this radiation. We do not worry about standing in front of car headlights, or putting in a 100 watt bulb.
The main radiation we worry about is ionizing radiation. This is the nasty stuff because it can lift electrons off of molecules and change chemical structures. We don't like this kind. But even this kind is probably less scary than you think.
Is plutonium a scary substance to you? Well it can certainly be used as fissile material, and the Pu238 form of it emits radiation certainly. Lots of it, but it is alpha radiation which cant even penetrate your skin. Its the Pu239 isotope that is more worrisome as that is the one used as fissile material and emits gamma rays. So even in the world of ionizing radiation, not everything is the bad stuff.
Most of the radiation we worry about are high energy radiation like X-rays and Gamma Rays which are ionizing. we don't really worry too much about non-ionizing radiation like visible light, infrared or radio waves like you get over your FM radio or TV.
These forms of radiation are generally absorbed (like how a black surface will absorb visible light) or reflected (like how a white surface reflects visible light) or transmitted (like visible light through glass). Often when one type of light is absorbed it may get emitted as another form of radiation. For example, when sunlight hits the earth the rocks and soil absorb the visible light and then emit some of that energy as infrared light (as a side note, the mechanism for global warming is due to the fact the CO2 transmits visible light but reflects infrared light, so sunlight goes right through it, hitting the earth ,which emits heat that gets reflected back).
OK, I hope this takes away some of the mystery of the scary word Radiation. If someone says radiation, the first question should be "What kind?".
Frequency: It appears that frequency is often equivocated with intensity, or power, or energy. It is of course none of these things. Frequency is simply the a measure of how many periods of a wave pass by in one second. So if we have scary radiation, like say ripples on a pond, you can count how many waves hit the edge of the pond in 10 seconds. You can then get the frequency, in Hertz (Hz) simply by dividing:
frequency=number of waves/number of seconds
The same goes for sound waves, radio waves, ultraviolet waves and gamma waves. In fact, the spectrum of frequencies is well mapped out, here is a terse one.
So if you look, there is a whole range of frequencies with names of things we are generally not afraid of: Visible light, infrared, radio. Smack in the middle of this list is microwaves.
Microwaves: The only reason microwaves sound scary is that we have devised machines that generate them to cook food. How does this work? Well, as I mentioned before, if an object absorbs one type of radiation, it will heat up and perhaps emit some energy as another type of radiation. This is what happens to your food in a microwave. The machine emits what is essentially light, at a different frequency than what we can see, which gets absorbed by the water in the food and heats the food. It heats so much that it cooks it. To be crystal clear, this is no different than sending infrared waves to your food to cook it like your stove or oven does. It does not cook your food from the inside out, anymore than your oven can cook your food from the inside out. The cool part about a microwave oven is that many of the plates and containers that we put in there transmit microwave radiation and therefore don't heat up (however some ceramics and glasses do absorb microwaves and do heat). The reason that it heats your food is that the power of the emitter is very high and the frequency of the microwave is tuned for optimal water absorption, which happens to be about 2.45 gigahertz. The reason you don't want to stick your hand in a microwave is because it will cook, not because of any effects of ionizing radiation.
One more note about radiation: you are constantly exposed to it. There is ionizing radiation from space and from the ground, you get exposure from CAT scans and X-Rays at your doctors office, you get it from all around you. Only a small fraction of the radiation you are exposed to comes from consumer products, combined!
Well this was just a short primer on electromagnetic phenomena, I hope it demystified some of it for you. Its not magic and it is well understood. Now, on to some quick misunderstandings:
There is no conclusive evidence that cell phones or power lines cause cancer. Cell phone towers don't cause suicide rates to rise.
You cant pop popcorn with cell phones. Your microwave can pop popcorn, not solely due to the frequency but mostly because of the power. A microwave oven produces in the range of 700 watts of microwave power that gets converted to heat in the water inside the popcorn (popcorn pops due to the water inside of each kernel). A cell phone only puts out 1 to 3 watts, its simply not enough power to boil water of any significant amount.
I think we are ready to talk about DECT radio systems.
What is DECT?
Digital Enhanced Cordless Technology is simply a standard, like NTSC for your television is a standard or like how there is an TCP/IP standard for your computer to communicate with the internet, or how there is a standard the defines the size and shape of your power outlet. The DECT standard defines the way the phone or baby monitor works. It defines the frequencies it will operate on, the way in encodes the voice data, the way it communicates with the hand set or base station, the power it will transmit at and a whole host of other things. You don't put DECT in a phone any more than you can put NTSC in a TV. The TV conforms to an NTSC standard and a DECT phone conforms to a DECT standard.
Yes, it operated the the area of the electromagnetic spectrum that we colloquially call 'microwaves'. No, it is not like a microwave oven. The frequencies it uses are not tuned to heat water and further, the specification fixes the transmission power to only 10 milliwatts (remember how much an oven uses?). Even if it used the exact same frequency as a microwave oven, the power is so abysmally small it wouldn't heat up a the water that fogs your glasses when you come from a humid area into an air conditioned one!
So what of this study I linked to? Their claim is that DECT phone lead to sleeplessness. The author of this article is very confused. Lets dig down a bit:
A major difference between the older cordless phone and the DECT cordless phones is that the DECT phone’s base station continuously emits pulsing microwave radiation at full power as long as the base station/charger is plugged into the 240 VAC wall socket. This means that the base station, usually placed on a bedside table, or on a work desk, is broadcasting a 2.4. or 5.8 GHz transmission (in Australia) regardless of whether the handset is charging in the base station cradle or being used 300 meters away.So what? The author is confusing frequency with power. Full power for this device, as previously mentioned is 10 milliwatts (25o milliwatts peak). Those pulses he is referring to, those are the peaks, most of the time the power is only 10 milliwatts. This is an amazingly low amount of power. The phone works well due to the way it encodes and transmits the information, not because it has a powerful signal.
in a New Zealand study on the health impacts on residents living near an AM and
FM radio tower in Ouruhia, NZ in 1998, there was a significant incidence of both chronic fatigue (37%) and sleep problems (35%).
This 'study' he refers to is simply not a scientific study as he implies. Its a report on the concerns of people who live near a n FM radio tower. Are you telling me that people who live near a a technology they don't understand that looks incredibly ugly are complaining? Remarkable. I'm floored. /sarcasm.
In a large-scale five-year study on people living near a short-wave transmitter in
Schwarzenburg, Switzerland, 55% of residents suffered from disturbed sleep, 35% from full insomnia.The researchers reported that “sleep difficulty was especially disturbing. This leads on to increasing fatigue and reduced feelings of well-being.”
Sleep difficulty leads to fatigue? No way. Of course its completely irrelevant. First you have to find that the radio tower actually causes sleep deprivation. A summary of the result he is referencing finds:
In the study conducted in 1992 an increased prevalence of sleep disturbances (problems of sleeping through) in the vicinity of the transmitter were demonstrated. The short time series analysis (three times 10 days) pointed in the same direction, however, these results, due to missing one-to-one exposure measurements, were difficult to interpret. We were not able to do person oriented measurements of exposure at that time and we still couldn’t do it today because of the unwieldy measurement equipment.So basically people can't sleep in the region but they were unable to directly associate it to the transmissions. It could have been traffic congestion, local economy causing stress, the smell of manure. Maybe the power supply for the phone is buzzing. Who knows?
In 1993 neither an acute nor a chronic effect on sleep quality or 6-OHMS could be demonstrated in humans. In cows no chronic effects were obtained either.I'll refrain from the sarcasm, and lastly..
In 1996 during another cross-sectional study it has been confirmed that sleep disturbances in the vicinity of the transmitter are more frequent as compared to the non-exposed control area. Furthermore, it could be shown that the exposed population applied coping measures by avoiding heavy meals and coffee consumption in the evening. There was a tendency for higher uptake of sleeping pills within the exposed area.The last two sentences are completely irrelevant. Yeah, sleeplessness sucks and people take pills if they cant sleep. That has zero to do with a radio tower in the area. But the conclusion lacks the justification, just like the 1992 summary. Is the zone of people that are close to the tower a high traffic area? are they low income? Here is their answer.. [crickets]
There are no conclusions after studying this for 10 years, and the author of the first article is unable to come up with any results of a study that is even a grade C.
He then goes into a litany of possible things DECT can cause. For this I refer you to the wackos that have the exact same list for Nutrasweet, milk, flouride, the mercury militia, and other unsupported causes of everything bad. ooh some are calling it Microwave illness.
Basically study after study after study shows that although people think that they have electromagnetic sensitivity, when actually testing in blind (grade B) conditions, they lose their ability to be sensitive to it any more. Its not that these people arent suffering, they are just trying to get relief from the wrong place. They need a therapist, not a scientist or a medical doctor.
If you arent worried about your TV, or sleeping near your cell phone, or having heated sheets or leaving your computer on, then you really shouldn't worry about the effects of a DECT phone. There is simply no mechanism by which it can bother you, and better than that, there is really no evidence that the actual tiny emmissions from any radio device actually affects anyone, mechanism or not.
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