In the close field area E-field/H-field varies with 1/(r^2) OR 1/(^3) depending on the source and nature of it. In addition at close distances similar fields may have an opposite vector polarity (close to EUT) and may partially cancel each other. In general it is not a good idea measuring close field components to draw conclusions on radiated emission components at greater distances, as these components do not actually radiate. That is why you won’t find any conversion factors for frequencies below 30 MHz, at distances shorter than the close-far field transition zone. (lambda/2pi)
Of course measurements in this area make sense about the EMI-level at the measurement point, and that is why some standards make measurements in the close field at a predefined distance. Changing that distance will make measurements incomparable. Regards, Ing. Gert Gremmen Approvals manager ------------------------------------------------------------------------------------ + ce marking of electrical/electronic equipment + Independent Consultancy Services + Compliance Testing and Design for CE marking according to EC-directives: - Electro Magnetic Compatibility 2014/30/EC - Electrical Safety 2014/35/EC - Radio & Telecommunication Terminal Equipment 99/5/EC Web: www.cetest.nl (English) www.ce-test.nl (Dutch) www.cetest.fr (under construction) Phone : +31 10 415 24 26 ------------------------------------------------------------------- This e-mail and any attachments thereto may contain information that is confidential and/or protected by intellectual property rights and are intended for the sole use of the recipient(s) named above. Any use of the information contained herein (including, but not limited to, total or partial reproduction, communication or distribution in any form) by persons other than the designated recipient(s) is prohibited. If you have received this e-mail in error, please notify the sender either by telephone or by e-mail and delete the material from any computer. Thank you for your co-operation. From: Grace Lin [mailto:graceli...@gmail.com] Sent: Tuesday 6 December 2016 00:46 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] EN 302 195 Distance Conversion Factor Dear Members, What is the appropriate distance conversion factor per EN 302 195, 9 kHz - 30 MHz? The limits were specified at 10m. Test data was too low to be detected at 10m and 3m. 1m distance was used to collect some data. EN 300 330 provides a chart for the distance conversion factors between 3m and 10m. It seems there is no such information in EN 302 195. Thank you very much for your time and I look forward to hearing from you. Best regards, Grace Lin - ---------------------------------------------------------------- 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
