RE: Cell phones and humans
Paolo, In my opinion, I agree with the "null" theory. I did some work in the '70's with a digital RG system operating at an assigned experimental frequency of 939+mHz. At this frequency, "line of sight" is extremely important, unlike lower frequency AM/FM radio signals, which often "bend" over the earth's curvature. We also experienced problems with isolated nulls. One of two things could have happened. She could have stepped into a null due to a blocked line of sight (and no strong refleced signal), or a null caused by an out-of-phase reflected signal. George --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Cell phones and humans
Paolo: Assuming that she was not wearing shoes at the time, then as she stepped back, with her feet already wet, she was likely still reasonably well grounded to the conductive concrete pool edge. I'll bet the explanation is more likely to be multipath cancellation; the RF null created by the addition of multiple signal reflections. Proving this might be difficult, since the null would be the product of ever reflection present in the pool vicinity that day. The position of every conductive object would need to be recreated. Regards, Ed :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) > -Original Message- > From: Roncone Paolo [mailto:paolo.ronc...@compuprint.it] > Sent: Saturday, September 23, 2000 3:19 PM > To: 'emc-p...@ieee.org ' > Subject: Cell phones and humans > > > > Group, > the subject of possible biological effects of cell phones is > having a lot of > attention these days and it was already touched in this > forum. I'd like to > get opinions about what my wife just told me. I don't know > if this should > be classified as "influence of cell phones on humans" or "influence of > humans on cell phones". The story is as follows: > my wife was talking on her cell phone while walking by a > swimming pool. As > she steppen right on the wet border of the pool (she was bare > foot) the line > went down. But just after stepping back on dry ground (just a > step or two > back, so the signal level shouldn't have changed so much) the > line got back > and she was able to resume her conversation. She told me she > didn't step > back again on the water, just to check if the phenomenon was > repeatable. I > honestly don't know if this is even worth of attention > because of course > it's not a "laboratory" or just even a "controlled" experiment. But if > anyone out there has any guess or thinks there is an > explanation... that > would be welcome !! > > Paolo > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson:pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Cell phones and humans
Paolo, This sounds like something worthy of investigation. My guess would be the effect of the wet concrete grounding the highly capacitive human body, effectively eliminating the bottom half of the dipole (The built in antenna is the top half). Of course, this probably only happens in marginal signal areas, as I've many times seen cell phones used in and around pools. Some time back I did some informal experiments with hand-held transceivers and portable receivers of various types. Some radios worked better with an earth ground wire attached to the chassis, and some worked worse. In some cases touching an earthed piece of metal with the free hand was enough to cause dramatic change in signal quality. Scott Lacey -Original Message- From: owner-emc-p...@ieee.org [mailto:owner-emc-p...@ieee.org]On Behalf Of Roncone Paolo Sent: Saturday, September 23, 2000 6:19 PM To: 'emc-p...@ieee.org ' Subject: Cell phones and humans Group, the subject of possible biological effects of cell phones is having a lot of attention these days and it was already touched in this forum. I'd like to get opinions about what my wife just told me. I don't know if this should be classified as "influence of cell phones on humans" or "influence of humans on cell phones". The story is as follows: my wife was talking on her cell phone while walking by a swimming pool. As she steppen right on the wet border of the pool (she was bare foot) the line went down. But just after stepping back on dry ground (just a step or two back, so the signal level shouldn't have changed so much) the line got back and she was able to resume her conversation. She told me she didn't step back again on the water, just to check if the phenomenon was repeatable. I honestly don't know if this is even worth of attention because of course it's not a "laboratory" or just even a "controlled" experiment. But if anyone out there has any guess or thinks there is an explanation... that would be welcome !! Paolo --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
