Ken et al,
I think the query was just the opposite. The tabletop is wooden, but do the legs need to be wooden as wel? The FCC paradigm (AFAIK) places the test sample 80 cm above ground, thus limiting parasitic capacity. My gut response is they should be fine with metal legs, as long as the tabletop is thick enough to limit stray capacity. If one had OCD tendencies, one could measure the capacity between a piece of metal laid on the tabletop and the ground plane, and as long as the capacity were suitably low (single-digit picofarads?) that would suffice. -- Ken Javor (256) 650-5261 From: Ken Wyatt <[email protected]> Reply-To: Ken Wyatt <[email protected]> Date: Thursday, December 28, 2023 at 3:53 PM To: <[email protected]> Subject: Re: [PSES] Metallic table for conducted emissions? Hi Brian, The answer is yes and no. Yes, you can get a general idea, but no, you really need a ground plane to conduct the CM currents back to the LISN, which needs to be bonded to the plane. Just find a metal supply store and buy enough aluminum to cover one of your benches. In a pinch, and for quick troubleshooting, I just tape down heavy duty aluminum foil and copper tape the LISN to the foil. You’ll see examples of the technique in my Volume 2, Chapter 3 of the trilogy. Cheers, Ken _______________________ I'm here to help you succeed! Feel free to call or email with any questions related to EMC or EMI troubleshooting - at no obligation. I'm always happy to help! Kenneth Wyatt Wyatt Technical Services LLC 56 Aspen Dr. Woodland Park, CO 80863 Contact Me! New Books! Web Site | Blog The EMC Blog (EDN) Subscribe to Newsletter Connect with me on LinkedIn On Dec 28, 2023, at 2:13 PM, Brian Gregory <[email protected]> wrote: Hello fellow experts, we're looking to build a conducted emission pre-compliance test station to FCC Part 15 Subpart B requirements (residential applications). Is a non-metallic table a necessity for reasonable accuracy? We have a number of lab benches with wood tops and metal legs that would fit far better than jamming an all wooden, non-folding table into our modest space. thanks all and Happy New Year, Colorado Brian 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 All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 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 All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher at: [email protected] To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 - ---------------------------------------------------------------- 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
