Constructive vs. destructive interference. Ken Javor Phone: (256) 650-5261
From: Bill Owsley <[email protected]> Reply-To: Bill Owsley <[email protected]> Date: Fri, 23 Dec 2011 19:25:13 -0800 (PST) To: "ce-test, qualified testing bv - Gert Gremmen" <[email protected]>, John Woodgate <[email protected]>, "[email protected]" <[email protected]> Subject: Re: Semi-Anechoic Chamber Question - Correction Factor And the effect of this phase shift, or no phase shift, would be...??? From: "ce-test, qualified testing bv - Gert Gremmen" <[email protected]> To: John Woodgate <[email protected]>; [email protected] Sent: Friday, December 23, 2011 4:58 AM Subject: RE: Semi-Anechoic Chamber Question - Correction Factor It's relevant to understand between vertically polarized waves that have a 180 degree phase shift on reflection, and horizontally polarized waves that do not. Regards, Ing. Gert Gremmen, BSc [email protected] www.cetest.nl <http://www.cetest.nl> Kiotoweg 363 3047 BG Rotterdam T 31(0)104152426 F 31(0)104154953 Before printing, think about the environment. -----Oorspronkelijk bericht----- Van: [email protected] [mailto:[email protected]] Namens John Woodgate Verzonden: Thursday, December 22, 2011 7:30 PM Aan: [email protected] Onderwerp: Re: Semi-Anechoic Chamber Question - Correction Factor In message <[email protected]>, dated Thu, 22 Dec 2011, Cortland Richmond <[email protected]> writes: >On 12/22/2011 9:27 AM, John Woodgate wrote: >> If the direct and reflected rays are equal amplitude and in phase, >>then it's +6 dB; if they are at 180 degrees, it's minus infinity dB. >>In between you can get any value, depending on relative phase and >>transmission loss. > >Equal amplitude only occurs if the direct and reflected paths are the >same distance. A 3 meter OATS can never meet that condition. If the >source and antenna are at 1 meter height, the reflected path is 3.6 >meters long My explanation, including 'If', was in the context of doubt between 3 dB and 6 dB. Your further information is relevant, but doesn't invalidate what I wrote. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk <http://www.jmwa.demon.co.uk> and www.isce.org.uk <http://www.isce.org.uk> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Some people who are peeling the finch of the financial crisis are thinking of biting a rook. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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To post a message to the list, send your e-mail to <[email protected]> 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://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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - ---------------------------------------------------------------- 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 <[email protected]> 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://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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- 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 <[email protected]> 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://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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
