Hi All, my comment might not fit exactly into this thread but during my tests I made the observation that on some EUTs the emissions got worse when cables were removed. This happened mostly in the frequency range beyond 300MHz but also below.
For the moment I have two theories on that: There are cancellation effects on the critical frequencies with the full cable configuration. The fact that a cable is attached or not influences the common-mode currents on the surface of the enclosure in direction and magnitude. This makes some slots in the enclosure more or less efficient antennas depending on the current in that area. The first theory suits more for the low-frequency range (<300MHz) in my eyes and the second one for the rest. I am chewing on that one for a little while but neither have the time nor the means to explore these theories further. I am curious on your comments. For the moment these are just theories ... Any similar experiences? Best regards, Michael > -----Original Message----- > From: Charles Grasso [mailto:cgrassospri...@earthlink.net] > Sent: Dienstag, 8. Juli 2003 05:59 > To: Ken Javor; Emc-Pstc; charles.gra...@echostar.com > Subject: RE: cable maximization - do you or don't you?? > > > > Hi Ken, > > Ahh the emissions analogy to the immunity tests? Hey - why not? > After all there are plenty of conditions that arise NOT as an > EUT problem but rather the artifical test environment that > we use - i.e the OATS. We could then properly use a CALC > without worrying about the cable radiation per se. > > Otts equation (derived from Banalis) is pretty accurate to > half a wave length - the trick is what do you do after that? > (Actually we have developed a correction factor here at > Echostar..stay tuned..) > > -----Original Message----- > From: owner-emc-p...@majordomo.ieee.org > [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Ken Javor > Sent: Monday, July 07, 2003 8:29 AM > To: Charles Grasso; Emc-Pstc; charles.gra...@echostar.com > Subject: Re: cable maximization - do you or don't you?? > > > > An excellent opportunity to ask a question of list members, > especially those > involved in standards writing. > > Why not calculate the cable conducted emission that would > result in radiated > spec level compliance, and levy a cable conducted emission > requirement? > > Then OATS testing would not require cable manipulation, and > any out of spec > conditions would result from test sample enclosure emissions. > > > From: "Charles Grasso" <cgrassospri...@earthlink.net> > > Reply-To: "Charles Grasso" <cgrassospri...@earthlink.net> > > Date: Sun, 6 Jul 2003 13:53:40 -0700 > > To: "Emc-Pstc" <emc-p...@ieee.org>, <charles.gra...@echostar.com> > > Subject: cable maximization - do you or don't you?? > > > > > > Hi all, > > > > I have recently run into an issue with an OEM > > supplier. The product that we are looking at > > fails emissions after cable maximization. > > In an informal study, I discovered that quite > > a few labs don't seem to perform cable maximization > > on a routine basis. ANSIC63 is quite clear on this > > - the cables need to be maximized. > > > > Is cable maximization a thing of the past - to > > be written out - and test labs are maximizing > > throughput rather than cables OR is is something > > I should continue to insist on?? > > > > Comments will be gratefully accepted. > > Charles Grasso > > EchoStar Communicationa > > > > ------------------------------------------- > > 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: emc_p...@symbol.com > > > > For policy questions, send mail to: > > Richard Nute: ri...@ieee.org > > Jim Bacher: j.bac...@ieee.org > > > > Archive is being moved, we will announce when it is back on-line. > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > > > > > ------------------------------------------- > 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: emc_p...@symbol.com > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > Archive is being moved, we will announce when it is back on-line. > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > > > ------------------------------------------- > 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: emc_p...@symbol.com > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > Archive is being moved, we will announce when it is back on-line. > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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