Groups > sci.electronics.design > #464601

Re: EMI problems

Newsgroups	sci.electronics.design
Date	2017-06-15 14:02 -0700
References	<gaf3kc5s96hufpak4qqm6avol7g05r27rc@4ax.com> <-eednRZkVPLrQd_EnZ2dnUU7-LmdnZ2d@giganews.com> <o3s5kct2q5n60u47fmjmbbr75e84aaalak@4ax.com>
Message-ID	<5c04783a-e4df-41b2-9f89-9fa1fe5343ae@googlegroups.com> (permalink)
Subject	Re: EMI problems
From	Lasse Langwadt Christensen <langwadt@fonz.dk>

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Den torsdag den 15. juni 2017 kl. 22.56.01 UTC+2 skrev John Larkin:
> On Thu, 15 Jun 2017 14:14:08 -0500, Jon Elson <jmelson@wustl.edu>
> wrote:
> 
> >John Larkin wrote:
> >
> >> The *output* of the amp needs to be around 10 nV/rootHz.
> >> 
> >Yikes!
> >> The DUT output is 100 ohm differential, which makes it harder. So we
> >> took one of our standard products, an x100 1GHz amplifier, and hacked
> >> a wideband transformer into the front end. Then I stuffed the DUT and
> >> the X100 amp into a custom-machined shielded enclosure.
> >> 
> >> 
> >https://dl.dropboxusercontent.com/u/53724080/Bypassing/E2_EMI_Encllosure.JPG
> >> 
> >> The DUT is the smaller extruded box. There's enough gain that I can
> >> use a scope to measure RMS noise voltage directly.
> >> 
> >> Those are really nice shield cans, but before you can use them you
> >> have to find a way to dispose of the filler materials that they come
> >> with.
> >> 
> >> 
> >OK, you might have to add another box and build a PI filter at the power 
> >entry.  With those DAMN transmitting antennas so close, you need SERIOUS 
> >filtering.  There's another power entry that is powering the X100 amp that 
> >looks to NOT have a feedthrough cap.  That likely is the real culprit.
> >
> >Jon
> 
> We are staring up at 22 megawatts that pack the entire spectrum. In a
> wooden building. I bet I could light an LED with a small antenna.
> 
> I have a cap across the amp power connector on the inside. It's from a
> switching wall wart! The DUT power (+-6V) comes through 3.3nF feedthru
> caps, ebay bag-o from Lithuania.
> 
> It seems to work! I'm seeing 15 mV RMS reported by the scope.
> Correcting for the X100 amp, and the 200 MHz scope bandwidth, the 100
> MHz noise is 106 uV RMS, 10.6 nV/rtHz. The noise spectrum looks flat
> up to the scope's 200 MHz rolloff, so the 100 MHz correction is mostly
> honest.
> 
> I had to bolt both boxes to the bottom of the cookie can, for good
> grounding.
> 
> Should we ship a Danish Butter Cookie can with each production unit?

in gold?  http://www.freundcontainer.com/gold-slip-cover-cans-square/p/6610T30GLD/

Thread

EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-14 16:09 -0700
  Re: EMI problems Martin Riddle <martin_ridd@verizon.net> - 2017-06-14 20:05 -0400
    Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-14 18:01 -0700
      Re: EMI problems o pere o <me@somewhere.net> - 2017-06-15 09:28 +0200
        Re: EMI problems Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-06-15 10:59 -0400
          Re: EMI problems Don Kuenz <g@crcomp.net> - 2017-06-21 02:53 +0000
        Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-15 07:59 -0700
          Re: EMI problems George Herold <gherold@teachspin.com> - 2017-06-15 08:07 -0700
            Re: EMI problems Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-06-15 11:12 -0400
              Re: EMI problems George Herold <gherold@teachspin.com> - 2017-06-15 08:42 -0700
            Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-15 09:38 -0700
          Re: EMI problems Robert Baer <robertbaer@localnet.com> - 2017-06-16 22:06 -0800
  Re: EMI problems Jon Elson <jmelson@wustl.edu> - 2017-06-15 14:14 -0500
    Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-15 13:55 -0700
      Re: EMI problems Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-06-15 14:02 -0700
      Re: EMI problems Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-06-16 12:43 -0400
        Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-16 10:11 -0700
          Re: EMI problems Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-06-16 13:24 -0400
      Re: EMI problems Jeff Liebermann <jeffl@cruzio.com> - 2017-06-16 10:37 -0700
      Re: EMI problems Jon Elson <jmelson@wustl.edu> - 2017-06-16 13:31 -0500
        Re: EMI problems Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-06-16 14:46 -0400
          Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-16 12:25 -0700
          Re: EMI problems George Herold <gherold@teachspin.com> - 2017-06-16 13:07 -0700
        Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-16 12:22 -0700
    Re: EMI problems upsidedown@downunder.com - 2017-06-16 09:35 +0300
      Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-16 06:40 -0700
  Re: EMI problems Joerg <news@analogconsultants.com> - 2017-06-15 12:27 -0700
    Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-15 12:47 -0700
      Re: EMI problems Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-06-15 12:57 -0700
        Re: EMI problems Joerg <news@analogconsultants.com> - 2017-06-15 13:12 -0700
      Re: EMI problems Joerg <news@analogconsultants.com> - 2017-06-15 13:03 -0700
    Re: EMI problems "Lund-Nielsen, Jorgen" <jorgen.lund-nielsen@xyz123desy.de> - 2017-06-16 08:58 +0200
  Re: EMI problems Jeff Liebermann <jeffl@cruzio.com> - 2017-06-16 10:03 -0700
    Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-16 11:09 -0700
      Re: EMI problems Jeff Liebermann <jeffl@cruzio.com> - 2017-06-16 12:06 -0700
        Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-16 12:34 -0700
          Re: EMI problems Jeff Liebermann <jeffl@cruzio.com> - 2017-06-17 09:22 -0700
            Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-17 10:08 -0700
              Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-17 11:07 -0700
                Re: EMI problems Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-06-17 21:30 +0300
                Re: EMI problems pcdhobbs@gmail.com - 2017-06-17 16:34 -0700
                Re: EMI problems krw@notreal.com - 2017-06-17 20:44 -0400
                Re: EMI problems George Herold <gherold@teachspin.com> - 2017-06-19 06:03 -0700
              Re: EMI problems Jeff Liebermann <jeffl@cruzio.com> - 2017-06-18 12:49 -0700
                Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-18 13:42 -0700
                Re: EMI problems Jeff Liebermann <jeffl@cruzio.com> - 2017-06-18 15:50 -0700
                Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-18 17:15 -0700
                Re: EMI problems upsidedown@downunder.com - 2017-06-19 09:39 +0300
                Re: EMI problems upsidedown@downunder.com - 2017-06-19 09:48 +0300
                Re: EMI problems Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-06-19 12:45 -0400
    Re: EMI problems "John Miles, KE5FX" <jmiles@gmail.com> - 2017-06-16 15:30 -0700
      Re: EMI problems John Larkin <jjlarkin@highland_snip_technology.com> - 2017-06-16 18:10 -0700
        Re: EMI problems Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-06-17 11:08 -0400
      Re: EMI problems upsidedown@downunder.com - 2017-06-17 14:25 +0300
      Re: EMI problems Jeff Liebermann <jeffl@cruzio.com> - 2017-06-17 09:35 -0700
        Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-17 10:42 -0700
  Re: EMI problems upsidedown@downunder.com - 2017-06-17 14:45 +0300
    Re: EMI problems John Larkin <jjlarkin@highlandtechnology.com> - 2017-06-17 08:28 -0700

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