Distributed capacitance from one segment to another will tend to short out the effects of these so-called loops, and the short gets better as the frequency gets higher. ps. that short is lower impedance than an open and higher than a solid plane that eliminates or minimizes loops. At frequencies above audio, the current loop is along the path of least impedance, which in not where one might look for it. It's a well documented experiment in numerous EMC seminars.
Bill In the event of a national emergency, click on the following links to provide directions to your duly elected mis-representatives. http://www.usa.gov/Contact/Elected.shtml or... https://writerep.house.gov/writerep/welcome.shtml http://www.senate.gov/general/contact_information/senators_cfm.cfm if really desperate... http://www.usa.gov/Contact/Elected.shtml --- On Thu, 9/30/10, John Woodgate <[email protected]> wrote: From: John Woodgate <[email protected]> Subject: Re: [PSES] EMI issue with Ethernet To: [email protected] Date: Thursday, September 30, 2010, 6:33 AM In message <[email protected]>, dated Thu, 30 Sep 2010, "ce-test, qualified testing bv - Gert Gremmen" <[email protected]> writes: > > Ethernet problems are happening in the 100-300 MHz region. There it works. Agreed, but my point is valid. It's not true that loops only matter at low frequencies. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If at first you don't succeed, delegate. But I support unbloated email http://www.asciiribbon.org/ - ---------------------------------------------------------------- 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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]>
