Curious Other Brian:
I did a field survey about 10 years ago at various rapid transit stations, with my antennas set up 2 meters away from the electronic faregates. (Why 2 meters? That was close as I could get to the faregates without the customers being able to grab my antennas. Oh yes, they did try!) I found that the customer carried electronics was the worst EMI threat to our faregates. And interestingly, in all the bands, the customer electronics managed to generate about 5 to 10 V/M. I saw 27 MHz CB sets, ham 2-meter transceivers, 150 MHz public service radios (from the electricians and other service workers), 450 MHz police radios, 800 MHz cell phones and 1600 MHz phones too. Generally, the emitter power decreased as frequency rose, but antenna efficiency increased, so the field strength was surprisingly predictable. Of course, as John Woodgate points out, a cell phone could well be placed so close to a home appliance that field strength becomes wildly unpredictable. True, this data is 10 years old, but I don't see any reason for the results to not still be a good guide. Since I like 6 dB margins, I would propose a minimum of 20 V/M immunity level for any electronic gadget exposed to the general public. Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military & Avionics EMC Is Our Specialty > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf > Of Kunde, Brian > Sent: Monday, August 24, 2009 11:24 AM > To: emc-p...@ieee.org > Subject: RE: Ring Of Fire? Cell Phone Turns On Oven - Popcorn II? > > Can anyone confirm that a cell phone can generate 10V/m or > more at any reasonable distance? [lets say 1 meter]. I didn't > think the transmitter was that powerful. > > We played around with a cell phone and our isotropic probe > and we couldn't get a reading over a few V/m unless we put > the phone right up against the antenna cone. And then, the > maximum we read was around 30V/m, but again, that was with > the phone touching the antenna of the probe. > > Curious. > > The Other Brian - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
