Ian, A signal that strong suggests one possibility to me. It is possible that the board layout was automatically routed. As a result a clock trace was run through the Ethernet magnetics area. This area should be clear of everything but the Ethernet signals. The application notes for the Ethernet interface chipset or magnetics may be of help.
If you do find a clock trace routed in this area, try cutting the trace, at both ends, and running a wire on the board and kept away >from all I/O ports. You may need to terminate your re-routed clock line. Of course this is only one possibility, but one I have encountered that caused a similar failure. Good luck. Eric Lifsey At 12:17 PM +0100 6/17/05, McBurney, Ian [Allen & Heath UK] wrote: >Dear colleagues; > >Can anyone advise me how to reduce the radiated emissions from a 100 >base-T Ethernet port with a UTP cable connected to below the EN55022 >class B limit? > >At the moment I am 20dB above the limit at 33MHz. Using STP only >reduces the emissions by 6dB. > >Thanks in advance; > >Ian McBurney. > >Allen & Heath Limited. > >email: [email protected] > >---------------------------------------------------------------- >This message is from the IEEE Product Safety Engineering Society >emc-pstc discussion list. Website: http://www.ieee-pses.org/ > >To post a message to the list, send your e-mail to [email protected] > >Instructions: http://listserv.ieee.org/listserv/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: > >Richard Nute: [email protected] Jim Bacher: [email protected] > >All emc-pstc postings are archived and searchable on the web at: > >http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
