Richard I have seen spikes because of turntables. Are you sure that the spikes are >from the turntable brushes rather than the motor? I would check the turntable motor as a possible problem and maybe reseat the mounting bolts (if you can). As to the chamber door I would also just keep everything clean. I used the conductive grease (and spray) and it always ended up collecting more dirt. I have used rubbing alcohol and water solutions and this worked ok but you are better off not using any grease in my opinion. Keep the surrounding area swept and clean and your door will stay clean.
Regards Dan _____ From: [email protected] [mailto:[email protected]] On Behalf Of Kunde, Brian Sent: Friday, October 06, 2006 12:19 PM To: Stone, Richard; IEEE EMC Discussion Group Subject: RE: Turntable conductive grease to minimize spikes Richard, Are you sure that is the cause of the spikes? We have a 4 meter turntable and have never seen spikes from it. I would think adding grease would promote the build up of dust and dirt and cause new problems. Am I lucky or are spikes common on turntables? We considered adding conductive greese to our chamber door so it would open and close easier and the overall consensus was DON'T. Again the dust and dirt issue. Currently we just keep it as clean as possible which helps. The Other Brian _____ From: [email protected] [mailto:[email protected]] On Behalf Of Stone, Richard Sent: Friday, October 06, 2006 2:50 PM To: [email protected]; IEEE EMC Discussion Group Subject: Turntable conductive grease to minimize spikes Group, is there a reccommended motorized turntable grease thats conductive to apply to the outer brushes of the turntable to minimize the spikes that popup on the spec. analyzer at times? This is occuring in the chamber I use now more than in the past. Thnak you Richard, _____ From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Friday, October 06, 2006 2:45 PM To: 'IEEE EMC Discussion Group' Subject: RE: Ethernet emissions It is not a "symbol rate". It is PLL in the Ethernet PHY that gets turned on as soon as you get a 100 or Gig link. So, when you connect the remote end, the 100 or Gig link comes up and you see it. The emission level, however, depends on many factors, mainly the PHY itself, the transformer, the PCB andsystem/enclosure design. Regards, Neven -------------- Original message -------------- From: "Stu Benner" <[email protected]> Derek, 125 MHz is the symbol rate of 100 Mb and 1 Gb Ethernet. Ensure that the shield of the cable, if used, is terminated properly at the chamber penetration, the UUT, and at the exercising equipment. If there is an increase in emissions when the shielded cable is installed, this could indeed indicate significant common mode signals are being coupled onto the outside of the shield of the cable. Regards, Stu Benner www.emcwizard.com <http://www.emcwizard.com/> From: [email protected] [mailto:[email protected]] On Behalf Of Derek Walton Sent: Wednesday, October 04, 2006 2:38 AM To: IEEE EMC Discussion Group Subject: Ethernet emissions HI All, I have a system on test that has a single very strong emission at about 125 MHz. Is this an Ethernet related frequency? It appears to jump 20 dB when the receive end, outside the chamber, is plugged in. Also, with unshielded cables it's not there. With shielded its about 30 dB up at the same frequency. Anyone have suggestions as to the source? Thanks, Derek Walton L F Research - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discus! sion li st. 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