Careful with the capacitance to ground - if I'm not mistaken by specification there can only be a few pf. I'm out of the office and don't have a reference handy. Could be wrong but you might want to check or maybe someone else can confirm/refute Gary
_____ From: [email protected] on behalf of [email protected] Sent: Tue 2/28/2006 7:17 AM To: [email protected] Subject: Re: Ethernet Decoupling If all else fails, you could used shielded Ethernet cable with a connector that makes ground contact. Don Borowski Schweitzer Engineering Labs Pullman, WA, USA "Price, Ed" <[email protected] om> To Sent by: [email protected] [email protected] cc Subject 02/28/2006 06:21 Ethernet Decoupling AM I have a twisted-pair Ethernet receive and a twisted-pair Ethernet transmit set of 4 wires penetrating what would otherwise be a shielded box. Internal box noise, as low as 35 MHz, is getting out along this path. I put a 4700 pF feedthrough capacitor on each of the four lines. That worked pretty well, so well that the Ethernet shut down. Does anyone have a guideline about how much capacitance, L-L & L-G, that is typically OK? Thanks in advance! Ed Price [email protected] WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty - ---------------------------------------------------------------- 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/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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This e-mail may contain SEL confidential or legally privileged information. The opinions expressed are not necessarily those of SEL. Any unauthorized disclosure, distribution or other use is prohibited. If you received this e-mail in error, please notify the sender, permanently delete it, and destroy any printed copies. - 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/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] 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/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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
