I know this is off subject, but just for fun, we put a cell phone a few inches away from our Field probe to see how high we could measure. When we yelled into the cell phone, we were seeing levels exceeding 60V/M. At a six foot distance we could hardly see the effects of the cell phone. It jumped around a lot and we could see numbers between 2-3 V/M if we shouted real loud. It was a nice waste of 15 minutes. Try it if you get bored. Brian ____________________Reply Separator____________________ Subject: Re: Why 3 and 10V/m? Author: [email protected] List-Post: [email protected] Date: 10/14/04 6:52 AM
Ian - I do not know the specific metric that defines 3 and 10V/m but it is tied to the expected exposure limits in these enviroments. In power distribution gear in the USA you can find ANSI C37.90.2 1995 was at 35V/M (no modulation) because that was the intensity of a 5W portable radio 6" from a product. This is supposed to represent the exposure due to work crews as they test out control circuits etc. Recently that standard was changed to be more in line with IEC61000-4-3 methods by shifting to 20V/M with the 80% 1Khz AM modulation. With the growth of the cell phone market I am surprised that the 3V/m limit has held. I understand that cell phone field strengths are greater than 3V/M but that is a near field measurement. I know there have been some changes recently - perhaps others can speak to that. Chris Wells From: "Gordon,Ian" <[email protected]> To: "'IEEE EMC-PSTC GROUP'" <[email protected]> Sent: Thursday, October 14, 2004 3:30 AM Subject: Why 3 and 10V/m? > All > Does anyone know why 3 and 10V/m were chosen for radiated immunity testing? > Obviously these are merely the minima to be used, but there must have been > some logic behind the values? > If you have information on the logic behind the levels chosen for other > tests then that would also be appreciated. > > Ian Gordon > > This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [email protected] Scott Douglas [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [email protected] Scott Douglas [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
