Only one comment: If you take this peg board to an OATS how can they maximize the cables?
-----Original Message----- From: Alex McNeil [mailto:alex.mcn...@ingenicofortronic.com] Sent: Tuesday, August 20, 2002 10:00 AM To: 'emc-p...@majordomo.ieee.org' Subject: Radiated Emissions setup Hi Forum, As we all know test setups are absolutely critical to EMC results. I have the good fortune of having a good pre-compliance radiated emissions site (3m OATS, Fully or Semi Anechoic Chamber). From using this site I see all sorts of "funnies" but still the most annoying is how much you can change the emission results just by changing cable positions. I carry out regular EMC audits and could never quite get the same results as 6 months previous, when that particular product was last tested (I keep the master product and was still getting different results due to setup). I now use an "Audit" board where I bundle the cables (30-40cm) in a particular "figure of 8" fashion via fixed wooden pegs. Thru' time I have convinced myself that this not only gives me worst case emissions but also that much sought after REPEATABILITY! I believe the setup is as per EN55022. I have a photograph* of this Audit board to allow this forum to comment on the good and the bad points of using such a system. Also, is there any reason I cannot take this Audit board to a Test House for Product Compliance testing and at the same time get correlation between a Compliance site and my own site? Photograph details (EUT with 3 X Serial Ports, PSTN and DC SELV power connection) 1. The 1M, 2M and 3M indicate the Horizontal bundling of cables from RS232 ports which would go to a tabletop EUT peripheral (or leave open circuit). The 3 lengths are connected to similar ports. This covers the different lengths issues. 2. The P is the inline power supply O/P cable going to the EUT. This is bundled vertically as it represents the power supply sitting on a customers floor. 3. The T is the PSTN telecomms cable. Again bundled vertically as it represents the cable going from the EUT to the wall socket. Finally, I have never understood the EN55022 figure 10 note 1 "If cables which hang closer than 40cm to the horizontal ground plane cannot be shortened to appropriate length, the excess shall be folded back and forth forming a bundle 30cm to 40cm long". Does this mean you can cut the cable to 1m or ? even though you will be shipping say 2m cables with the product? *I have not attached the photograph, 212Kb. This will be sent to those requesting it i.e. to those people who are thinking of commenting on this email. I look forward with interest to this forums comments. Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
