IIRC, the em wave has a spherical wave front but that is the surface of a sphere not the volume, so the square law applies. If it did fall off at a cubic rate there would might be more cause concern because you the wave energy at the transmitter would be much more intense to reach the target antenna.
As to Tom's question, the relationship between tranmission sources and radio waves is suspicious and being studied, but I don't know the signifigance of that. Anectdotaly, the fellows who manned the pirate radio stations in England were known to have their hair fall out. Also IIRC (perhaps not so germanely) the connection high voltage cancer is pretty established. Devra Davis author of the work in question is director of UoPitt's center for Environmental Oncology. Also, when NPR (specifically, Fresh Air in this case, interviews cranks they do tend to challenge some of their assertions, this was not that sort of interview and if I had to put money on whether it was Tom or Devra Davis who was talking out of their depth, well...) gerald <[EMAIL PROTECTED]> wrote: the part that is 2-3mm from your ear is a speaker. the radiation devise is housed elsewhere in the box. you are attempting to determine the distance of the mechanical device, which has nothing to do with electric radiation. I would presume the electronic portion of the blutooth device is much closer, as the whole thing is only a couple inches long. the electronic transmitter in my folding cell phone is in the bottom portion of my cell phone, and at least 4" from my ear. presuming the device transmits non directionally in 3 dimensions, would not the signal reduce by the cube of the distance? if it were to transmit directionally, the square root estimate may not work. most people in my neighbor hood hold the phone about 2' away, directly in front of themselves while driving down I95. this is to transmit and view images of the telephone talkers. At 08:13 AM 12/2/2007, you wrote: >Are bluetooth headphones actually closer than a cell phone >against the ear? If we are talking about the difference between >1/4 inch and 1/16 of an inch, equally powerful signals would >have differ by a factor 16 (ie 4 squared). >The power requirement to broadcast bluetooth 30feet compared to >a cell phone 10000 feet is different by a factor of >90,000. > >Given that I would expect that the incident energy of bluetooth radiation >on your body is many times (10? 100? 1000?) less than that of a cell phone. > > >Randy wrote: I did hear her on a few show while on her book tour and noted >her concern >about the potential harm from cell phones and about the research on this to >date. > >Re. bluetooth, is it definitely the case that it gives off much less >radiation than cellphones? Even if so I wonder about the effect of >something that close to the head, closer than even cellphones are held. But >as far as the bigger picture, long-term risk, you are probably right in that >cellphone use today probably wouldn't result in cancer for many years if not >decades, though radiation damage is cumulative so who knows if there isn't >some threshold tipping point. > >Randall > > >On Dec 1, 2007 1:50 PM, Paul Meyer > wrote: > >> If anyone listened to the public health academic who wrote >> "The Secret History of the War On Cancer" some of the most >> quoted studies >> done on cell phone radiation have severe methodological >> flaws and even if they were good might been inadequate for >> assessing the brain cancer risk 20 or 30 years out (which is >> the appropriate scale for the development of brain cancer) >> One >> reason minors should not have cell phones except for >> emergency use. >> >> That said, bluetooth would seem to be a much less intense >> radiation source and if it had 10 times less of cancer risk >> than cell phones, I would not be surprised in the slightest. >> >> The same advice about avoiding cell phones for minors goes for aspartame. >> >> Randy wrote: I was in a store checking out bluetooth >> headsets for cell phone, ending up >> getting one on sale for $15. However another customer I was talking to >> about cell phones, etc. said that bluetooth headpieces deliver as much >> radiation to the head as using the cellphone directly, near your head, >> maybe >> more. Bluetooth is one thing, bluebrain is another; anyone know if this >> is >> true? If so I may well return the bluetooth and just stick to regular, >> corded headpiece, which is admittedly less convenient. I vaguely recall >> this >> coming up here before but can't locate the posts. >> >> Randall >> >> >> >> -- >> Please use new email address: [EMAIL PROTECTED] >> >> >> ************************************************************************ >> * ==> QUICK LIST-COMMAND REFERENCE - Put the following commands in <== >> * ==> the body of an email & send 'em to: [EMAIL PROTECTED] <== >> * Join the list: SUBSCRIBE COMPUTERGUYS-L Your Name >> * Too much mail? Try Daily Digests command: SET COMPUTERGUYS-L DIGEST >> * Tired of the List? 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