Certainly radio frequency emissions measurement is far from an exact science, but that's probably just fine for what it is intended to do. Pass at one lab, fail at another seems to be a common theme, so there must be many variables at play.
I've read that, depending on antenna size, 3 metre distance is within what is called the "near field" and if so, then I assume spectrum of radio emission wouldn't correlate well to what would be measured at 10m or 30m. _______________________________________________________________________________ Ralph McDiarmid | Schneider Electric | Solar Business | CANADA | Regulatory Compliance Engineering From: John Woodgate <[email protected]> To: [email protected] Date: 10/16/2012 09:40 AM Subject: Re: [PSES] OATS vs FAR Radiated Emissions Limits In message <[email protected]>, dated Tue, 16 Oct 2012, "Pawson, James" <[email protected]> writes: >These limits are lower than those for an OATS at 3m. Does anyone know >why the limits are lower and of a different characteristic? I'm >guessing something to do with the lack of reflective ground plane in >the FAR. > In principle, an attempt has been made to reconcile the limits applicable to the different measurement environments so that products with given emission levels produce at least similar test results (dB above or, preferably, below the limit) in each environment. The deliberations that resulted in these limits were long and very complex. -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk The longer it takes to make a point, the more obtuse it proves to be. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- 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 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://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]>
