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Article #745Re: More on the Oscilloscope/Static pickup issue
From: RFI-EMI-GUY
Date: Wed, 29 Jul 2009 14:38
Date: Wed, 29 Jul 2009 14:38
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David L. Jones wrote: > notme wrote: >> On Sun, 26 Jul 2009 05:22:31 -0700, David L. Jones wrote >> (in article <%TXam.45224$3m2.4738@newsfe06.iad>): >> >>> http://www.edn.com/blog/1700000170/post/1120046912.html >> So, it's not a phenomenon of that scope, but an example of how long >> ground clips can get you into trouble at high frequencies, regardless >> the tool at the other end of the probe. > > Nothing to do with the long clip lead on the end, as I demonstrated. Regular > issues with long ground clips at high frequency is another problem entirely. > You can have the best and shortest ground clip possible and you'll still get > this effect, picked up by the probe coax. > And the latest video shows you don't even need the cable connected at all to > get a response. > > Enjoy. > Dave. Try with an older analog scope with a metal cabinet. I think you have uncovered a shielding weakness with the newer digital scopes. The resonant frequency is probably coincidental with the internal circuitry or groundplane geometry of the scope -- Joe Leikhim K4SAT "The RFI-EMI-GUY"� "Use only Genuine Interocitor Parts" Tom Servo ;-P
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X-Google-Thread: a5a6238865,5bba74dd82ef2ea2 X-Google-Attributes: gida5a6238865,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII Path: arc1-ca.pugleaf.net!g2news2.google.com!news1.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!nx02.iad01.newshosting.com!newshosting.com!69.16.185.51.MISMATCH!tmp-post01.iad!news.highwinds-media.com!not-for-mail Date: Wed, 29 Jul 2009 10:38:33 -0400 From: RFI-EMI-GUY <Rhyolite@NETTALLY.COM> User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 Newsgroups: sci.electronics.design,aus.electronics Subject: Re: More on the Oscilloscope/Static pickup issue References: <%TXam.45224$3m2.4738@newsfe06.iad> <0001HW.C691CB63009FA4D0B08A39AF@news.eternal-september.org> <r2Lbm.48322$ZN.32574@newsfe23.iad> In-Reply-To: <r2Lbm.48322$ZN.32574@newsfe23.iad> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Lines: 30 Message-ID: <4a705edb$0$4953$9a6e19ea@unlimited.newshosting.com> Organization: Newshosting.com - Highest quality at a great price! www.newshosting.com NNTP-Posting-Host: 70.121.42.161 X-Complaints-To: abuse@newshosting.com