JOHN's QUESTION That's all very well, but it only applies to the configuration and collection of peripherals, if any, that is under test, with ground plane, bundled cables etc. Is it REALLY appropriate to be so meticulous over that configuration, when the product in the field will never be operated like that?
Ans: Yes. After all the EMC community has (in its wisdom) is working on the assumption that tests performed at an artifical test environment (such as an OATS) will result in a well managed spectrum. If that assumption is wrong - then frankly - whats the point in ANY of this?? Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: [email protected] Email: [email protected]; Email Alternate: [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Chris Maxwell Sent: Tuesday, July 19, 2005 9:31 AM To: John Woodgate; [email protected] Subject: RE: EMC Ethics Hi guys...my last reply to this thread...honest. John's questions are relevant; and I don't take issue with them...I'm just replying because some may know what labs I use; and I want to make sure that no reputation is tarnished by leaving an open question. It's been a fun discussion; but I gotta get back to work...until the next thread piques my interest :-) My replies are outlined in asterisks below. From: [email protected] [mailto:[email protected]] On Behalf Of John Woodgate Sent: Tuesday, July 19, 2005 10:43 AM To: [email protected] Subject: Re: EMC Ethics Chris Maxwell <[email protected]> wrote (in <[email protected]>) about 'EMC Ethics', on Tue, 19 Jul 2005: >I've worked with a few labs over the last 9 years. At some labs, I >don't trust marginal data, at one I do...why? Because at that lab, if >there is a frequency that is passing by a dB or so...they do everything >they can in order to maximize the signal...they move cables, they raise >the antenna up and down, they rotate the table. It's nerve wracking to >watch as readings come up time and time again...all so close to the limit. JOHN's QUESTION That's all very well, but it only applies to the configuration and collection of peripherals, if any, that is under test, with ground plane, bundled cables etc. Is it REALLY appropriate to be so meticulous over that configuration, when the product in the field will never be operated like that? *************************************************************** REPLY: We often discuss configurations during the test; and we have backed out cables and configurations that wouldn't make sense in the real world. If you're a lab, and you're not meticulous with what you're given...then you're not a lab :-) **************************************************************** JOHN's QUESTION And do they also adopt the same procedure if the product FAILS by 1 dB (to find whether it is just one peripheral, or one critical and improbable arrangement of the cables that increases the emission by, say, 3 dB) or are they simply intent on failing it if at all possible? ************************************************************** REPLY I've never gotten the impression that they were just trying to fail our product. They troubleshoot failures just as hard as passes. ************************************************************* -- Regards, John Woodgate, OOO - Own Opinions Only. Deadlines are 90% of deadliness. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk 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 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
