Resending without the attached file. I think EMC-PSTC rejected the e-mail posting due to the attachment.
So here it is again without the attached file - should go through now. Manny Barron From: Manny Barron [mailto:[email protected]] Sent: Sunday, August 02, 2015 4:42 PM To: '[email protected]' Cc: 'Pawson, James'; 'John Woodgate'; 'ce-test, qualified testing bv - Gert Gremmen'; 'Heckrotte, Michael'; 'CR'; 'Brent DeWitt'; 'T.Sato' Subject: RE: [PSES] Calculating Reflection Angles on OATS/SAC Hi James, Back in 1998 when I wrote a paper for the IEEE EMC Symposium on calculating the "Theoretical Normalized Site Attenuation (NSA) by Spreadsheet Analysis", I needed to do a similar calculation as yours in order to determine the grazing angle gamma. I couldn't find an equation for this anywhere so I derived it myself (simple algebra, I believe some on this e-mail thread have already provided similar results). See the attached diagram with associated algebra - I am surprised I still had my old notes! Note: The file is attached only to direct e-mail's shown on cc: line. (because I believe the EMC-PSTC server strips off file attachments) If others are interested please send me an e-mail and I will send it to you. (not sure how else to distribute file attachments on this forum) Also, I still have the original Excel spreadsheet used for the paper noted above. It's one of the most complicated spreadsheets that I have ever generated plus it contains a macro to move the hypothetical antenna from 1 to 4 meters in small steps, storing the "Ed" value after each step (or using a Max Hold technique, I don't remember) and then determining "Ed(max)" after the antenna reaches 4 meters height. If anyone is interested in this spreadsheet please let me know and I will send it to you. Caution: It was created using Office 97 in Windows XP, so I don't know how well it works with the latest Office and Windows version (I tried it a few times today, and it appears to work okay). Lastly, there was another similar paper referenced in another e-mail on this thread: Barron, M., "3-D Surface Plot of Theoretical Normalized Site Attenuation Calculation by Spreadsheet Analysis", 2001 IEEE International Symposium on EMC, Seattle, WA. Pp 133-138. The updated paper I actually presented at the symposium never made it into the final symposium record so IEEExplore only has the old version. If anyone is interested in the updated version please send me an e-mail and I will send it to you. Hoping maybe this info may be helpful in some way. Manny Barron From: Pawson, James [mailto:[email protected]] Sent: Friday, July 31, 2015 7:59 AM To: [email protected] Subject: [PSES] Calculating Reflection Angles on OATS/SAC Hi, I'm trying to calculate the distances/angles at which a maximum (in phase) or minimum (anti-phase) signal would occur on an OATS/SAC. I can do this simply when the TX and RX antennae are the same height above the reflecting surface as the point of reflection lies halfway between the two antennae, Distance_tx = Distance_rx. The direct and reflected paths can be calculated using simple geometry and the wavelength is given by lambda = c / f. However when the height of the RX antenna is different to the height of the TX antenna then the horizontal distance to the reflection point is no longer equidistant. I can see that the ratio Height_tx / Distance_tx = Height_rx / Distance_rx remains the same because the angle of reflection is the same. But I'm left with two unknown Distance terms in the equation. Is there a standard equation for calculating the reflection angle on an OATS/SAC with a varying height antenna? Or can someone give me some pointers to help me figure it out myself? I was so distracted thinking about this that I missed my turnoff whilst cycling home the other day. I've tried Googling but maybe I'm not putting in the right search term. Any assistance gratefully received. Thanks and regards, James - ---------------------------------------------------------------- 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://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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
