If it helps, the EMC Handbook Vol. 4 (White) suggests that absorbing material (6dB loss) in an SAC reduces the error caused by all reflection (reinforced/cancellation) to about 4dB peak to peak.
Single bound path with no absorption seems to result in only about 3dB (peak to peak) error, according to White. _______________________________________________________________________________ Ralph McDiarmid | Schneider Electric | Solar Business | CANADA | Regulatory Compliance Engineering From: "Pawson, James" <[email protected]> To: [email protected], Date: 07/31/2015 08:17 AM 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 email has been scanned by the Symantec Email Security.cloud service. ______________________________________________________________________ - ---------------------------------------------------------------- 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://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]> - ---------------------------------------------------------------- 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://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]>
