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EMI problems

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  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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#464429 — EMI problems

I designed this little photodiode amp and I'm trying to measure its
output noise. All we can see on a spectrum analyser is radio and TV
stations.

https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG

The *output* of the amp needs to be around 10 nV/rootHz.

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.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#464448

On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
<jjlarkin@highland_snip_technology.com> wrote:

>
>
>I designed this little photodiode amp and I'm trying to measure its
>output noise. All we can see on a spectrum analyser is radio and TV
>stations.
>
>https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>
>The *output* of the amp needs to be around 10 nV/rootHz.
>
>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.

You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
you need more room.

Cheer

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#464468

On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
<martin_ridd@verizon.net> wrote:

>On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
><jjlarkin@highland_snip_technology.com> wrote:
>
>>
>>
>>I designed this little photodiode amp and I'm trying to measure its
>>output noise. All we can see on a spectrum analyser is radio and TV
>>stations.
>>
>>https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>>
>>The *output* of the amp needs to be around 10 nV/rootHz.
>>
>>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.
>
>You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>you need more room.
>
>Cheer

A square can would be better. It's a little weird bolting connectors
into the round one. This needs research.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#464509

On 15/06/17 03:01, John Larkin wrote:
> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
> <martin_ridd@verizon.net> wrote:
> 
>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
>> <jjlarkin@highland_snip_technology.com> wrote:
>>
>>>
>>>
>>> I designed this little photodiode amp and I'm trying to measure its
>>> output noise. All we can see on a spectrum analyser is radio and TV
>>> stations.
>>>
>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>>>
>>> The *output* of the amp needs to be around 10 nV/rootHz.
>>>
>>> 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.
>>
>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>> you need more room.
>>
>> Cheer
> 
> A square can would be better. It's a little weird bolting connectors
> into the round one. This needs research.
> 
> 

You can get squares... even without filler material!

https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html

Pere

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#464535

On 06/15/2017 03:28 AM, o pere o wrote:
> On 15/06/17 03:01, John Larkin wrote:
>> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
>> <martin_ridd@verizon.net> wrote:
>>
>>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
>>> <jjlarkin@highland_snip_technology.com> wrote:
>>>
>>>>
>>>>
>>>> I designed this little photodiode amp and I'm trying to measure its
>>>> output noise. All we can see on a spectrum analyser is radio and TV
>>>> stations.
>>>>
>>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>>>>
>>>> The *output* of the amp needs to be around 10 nV/rootHz.
>>>>
>>>> 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.
>>>
>>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>>> you need more room.
>>>
>>> Cheer
>>
>> A square can would be better. It's a little weird bolting connectors
>> into the round one. This needs research.
>>
>>
> 
> You can get squares... even without filler material!
> 
> https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
> 
> 
> Pere

For smaller stuff, I have a bin full of unused 70-mm nickel-plated steel
film cans that I got from Surplus Shed.  You put the connectors in the
lid. ;)

Clean paint cans work well too--there's a tea place in Maryland that
ships their teas in them.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

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#465093

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
> On 06/15/2017 03:28 AM, o pere o wrote:
>> On 15/06/17 03:01, John Larkin wrote:
>>> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
>>> <martin_ridd@verizon.net> wrote:
>>>
>>>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
>>>> <jjlarkin@highland_snip_technology.com> wrote:
>>>>
>>>>>
>>>>>
>>>>> I designed this little photodiode amp and I'm trying to measure its
>>>>> output noise. All we can see on a spectrum analyser is radio and TV
>>>>> stations.
>>>>>
>>>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>>>>>
>>>>> The *output* of the amp needs to be around 10 nV/rootHz.
>>>>>
>>>>> The *output* of the amp needs to be around 10 nV/rootHz.
>>>>>
>>>>> 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.
>>>>
>>>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>>>> you need more room.
>>>>
>>>> Cheer
>>>
>>> A square can would be better. It's a little weird bolting connectors
>>> into the round one. This needs research.
>>>
>>>
>>
>> You can get squares... even without filler material!
>>
>> https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
>>
>>
>> Pere
>
> For smaller stuff, I have a bin full of unused 70-mm nickel-plated steel
> film cans that I got from Surplus Shed.  You put the connectors in the
> lid. ;)
>
> Clean paint cans work well too--there's a tea place in Maryland that
> ships their teas in them.

Empty Altoids tins also work and have an iconic design language. In this
case the connectors work best on the side.

Altoids jelly bean mixer
http://crcomp.net/ee/Altoids%20jelly%20bean%20mixer/

Thank you,

--
Don, KB7RPU

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#464537

On Thu, 15 Jun 2017 09:28:36 +0200, o pere o <me@somewhere.net> wrote:

>On 15/06/17 03:01, John Larkin wrote:
>> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
>> <martin_ridd@verizon.net> wrote:
>> 
>>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
>>> <jjlarkin@highland_snip_technology.com> wrote:
>>>
>>>>
>>>>
>>>> I designed this little photodiode amp and I'm trying to measure its
>>>> output noise. All we can see on a spectrum analyser is radio and TV
>>>> stations.
>>>>
>>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>>>>
>>>> The *output* of the amp needs to be around 10 nV/rootHz.
>>>>
>>>> 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.
>>>
>>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>>> you need more room.
>>>
>>> Cheer
>> 
>> A square can would be better. It's a little weird bolting connectors
>> into the round one. This needs research.
>> 
>> 
>
>You can get squares... even without filler material!
>
>https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
>
>Pere

But I want cookies!


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#464541

On Thursday, June 15, 2017 at 11:00:06 AM UTC-4, John Larkin wrote:
> On Thu, 15 Jun 2017 09:28:36 +0200, o pere o <me@somewhere.net> wrote:
> 
> >On 15/06/17 03:01, John Larkin wrote:
> >> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
> >> <martin_ridd@verizon.net> wrote:
> >> 
> >>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
> >>> <jjlarkin@highland_snip_technology.com> wrote:
> >>>
> >>>>
> >>>>
> >>>> I designed this little photodiode amp and I'm trying to measure its
> >>>> output noise. All we can see on a spectrum analyser is radio and TV
> >>>> stations.
> >>>>
> >>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
> >>>>
> >>>> The *output* of the amp needs to be around 10 nV/rootHz.
> >>>>
> >>>> 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.
> >>>
> >>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
> >>> you need more room.
> >>>
> >>> Cheer
> >> 
> >> A square can would be better. It's a little weird bolting connectors
> >> into the round one. This needs research.
> >> 
> >> 
> >
> >You can get squares... even without filler material!
> >
> >https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
> >
> >Pere
> 
> But I want cookies!
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> 
> lunatic fringe electronics

10nV/Hz sounds hard.  

How about short bread.... (searching for cookies in square tins.)
https://www.ebay.com/i/272715063105?chn=ps&dispItem=1

George H. 

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#464542

On 06/15/2017 11:07 AM, George Herold wrote:
> On Thursday, June 15, 2017 at 11:00:06 AM UTC-4, John Larkin wrote:
>> On Thu, 15 Jun 2017 09:28:36 +0200, o pere o <me@somewhere.net> wrote:
>>
>>> On 15/06/17 03:01, John Larkin wrote:
>>>> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
>>>> <martin_ridd@verizon.net> wrote:
>>>>
>>>>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
>>>>> <jjlarkin@highland_snip_technology.com> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> I designed this little photodiode amp and I'm trying to measure its
>>>>>> output noise. All we can see on a spectrum analyser is radio and TV
>>>>>> stations.
>>>>>>
>>>>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>>>>>>
>>>>>> The *output* of the amp needs to be around 10 nV/rootHz.
>>>>>>
>>>>>> 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.
>>>>>
>>>>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>>>>> you need more room.
>>>>>
>>>>> Cheer
>>>>
>>>> A square can would be better. It's a little weird bolting connectors
>>>> into the round one. This needs research.
>>>>
>>>>
>>>
>>> You can get squares... even without filler material!
>>>
>>> https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
>>>
>>> Pere
>>
>> But I want cookies!
>>
>>
>> -- 
>>
>> John Larkin         Highland Technology, Inc
>>
>> lunatic fringe electronics
> 
> 10nV/Hz sounds hard.  

Well, it depends on the gain, the bandwidth, and the photodiode
capacitance.  Your average 20-dB amplifier with a 50-ohm input is better
than that, for instance, and some are _much_ better.

Cheers

Phil Hobbs


> 
> How about short bread.... (searching for cookies in square tins.)
> https://www.ebay.com/i/272715063105?chn=ps&dispItem=1
> 
> George H. 
> 


-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

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#464551

On Thursday, June 15, 2017 at 11:12:21 AM UTC-4, Phil Hobbs wrote:
> On 06/15/2017 11:07 AM, George Herold wrote:
> > On Thursday, June 15, 2017 at 11:00:06 AM UTC-4, John Larkin wrote:
> >> On Thu, 15 Jun 2017 09:28:36 +0200, o pere o <me@somewhere.net> wrote:
> >>
> >>> On 15/06/17 03:01, John Larkin wrote:
> >>>> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
> >>>> <martin_ridd@verizon.net> wrote:
> >>>>
> >>>>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
> >>>>> <jjlarkin@highland_snip_technology.com> wrote:
> >>>>>
> >>>>>>
> >>>>>>
> >>>>>> I designed this little photodiode amp and I'm trying to measure its
> >>>>>> output noise. All we can see on a spectrum analyser is radio and TV
> >>>>>> stations.
> >>>>>>
> >>>>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
> >>>>>>
> >>>>>> The *output* of the amp needs to be around 10 nV/rootHz.
> >>>>>>
> >>>>>> 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.
> >>>>>
> >>>>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
> >>>>> you need more room.
> >>>>>
> >>>>> Cheer
> >>>>
> >>>> A square can would be better. It's a little weird bolting connectors
> >>>> into the round one. This needs research.
> >>>>
> >>>>
> >>>
> >>> You can get squares... even without filler material!
> >>>
> >>> https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
> >>>
> >>> Pere
> >>
> >> But I want cookies!
> >>
> >>
> >> -- 
> >>
> >> John Larkin         Highland Technology, Inc
> >>
> >> lunatic fringe electronics
> > 
> > 10nV/Hz sounds hard.  
> 
> Well, it depends on the gain, the bandwidth, and the photodiode
> capacitance.  Your average 20-dB amplifier with a 50-ohm input is better
> than that, for instance, and some are _much_ better.
> 
Well in my rather slow (opamp) world Fet opamps start off at ~10 nV/rtHz
and noise only gets worse in a TIA.  (of course you know all that.)

And right, there are some better Fet opamps these days.  

George H. 
> Cheers
> 
> Phil Hobbs
> 
> 
> > 
> > How about short bread.... (searching for cookies in square tins.)
> > https://www.ebay.com/i/272715063105?chn=ps&dispItem=1
> > 
> > George H. 
> > 
> 
> 
> -- 
> Dr Philip C D Hobbs
> Principal Consultant
> ElectroOptical Innovations LLC
> Optics, Electro-optics, Photonics, Analog Electronics
> 
> 160 North State Road #203
> Briarcliff Manor NY 10510
> 
> hobbs at electrooptical dot net
> http://electrooptical.net

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#464561

On Thu, 15 Jun 2017 08:07:09 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

>On Thursday, June 15, 2017 at 11:00:06 AM UTC-4, John Larkin wrote:
>> On Thu, 15 Jun 2017 09:28:36 +0200, o pere o <me@somewhere.net> wrote:
>> 
>> >On 15/06/17 03:01, John Larkin wrote:
>> >> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
>> >> <martin_ridd@verizon.net> wrote:
>> >> 
>> >>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
>> >>> <jjlarkin@highland_snip_technology.com> wrote:
>> >>>
>> >>>>
>> >>>>
>> >>>> I designed this little photodiode amp and I'm trying to measure its
>> >>>> output noise. All we can see on a spectrum analyser is radio and TV
>> >>>> stations.
>> >>>>
>> >>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>> >>>>
>> >>>> The *output* of the amp needs to be around 10 nV/rootHz.
>> >>>>
>> >>>> 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.
>> >>>
>> >>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>> >>> you need more room.
>> >>>
>> >>> Cheer
>> >> 
>> >> A square can would be better. It's a little weird bolting connectors
>> >> into the round one. This needs research.
>> >> 
>> >> 
>> >
>> >You can get squares... even without filler material!
>> >
>> >https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
>> >
>> >Pere
>> 
>> But I want cookies!
>> 
>> 
>> -- 
>> 
>> John Larkin         Highland Technology, Inc
>> 
>> lunatic fringe electronics
>
>10nV/Hz sounds hard.  
>
>How about short bread.... (searching for cookies in square tins.)
>https://www.ebay.com/i/272715063105?chn=ps&dispItem=1
>
>George H. 

The overall voltage gain is only 3. I used two parallel gain paths,
resistively summed at the output, to reduce noise by sqrt(2).

Shortbread is good; I'll try some. I hope that can is solderable.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#464796

John Larkin wrote:
> On Thu, 15 Jun 2017 09:28:36 +0200, o pere o<me@somewhere.net>  wrote:
>
>> On 15/06/17 03:01, John Larkin wrote:
>>> On Wed, 14 Jun 2017 20:05:21 -0400, Martin Riddle
>>> <martin_ridd@verizon.net>  wrote:
>>>
>>>> On Wed, 14 Jun 2017 16:09:43 -0700, John Larkin
>>>> <jjlarkin@highland_snip_technology.com>  wrote:
>>>>
>>>>>
>>>>>
>>>>> I designed this little photodiode amp and I'm trying to measure its
>>>>> output noise. All we can see on a spectrum analyser is radio and TV
>>>>> stations.
>>>>>
>>>>> https://dl.dropboxusercontent.com/u/53724080/Otis/EMI/Sutro.JPG
>>>>>
>>>>> The *output* of the amp needs to be around 10 nV/rootHz.
>>>>>
>>>>> 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.
>>>>
>>>> You can still get the 'Charles Chips' 1 lb tin. It's a tad bigger if
>>>> you need more room.
>>>>
>>>> Cheer
>>>
>>> A square can would be better. It's a little weird bolting connectors
>>> into the round one. This needs research.
>>>
>>>
>>
>> You can get squares... even without filler material!
>>
>> https://es.aliexpress.com/store/product/Size-180x130x72mm-tin-box-food-tin-can-cookies-box-biscuit-metal-box-gift-container-storage-box/713943_32297655507.html
>>
>> Pere
>
> But I want cookies!
>
>
   Your browser eats them like crazy!

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#464579

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

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#464599

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?



-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#464601

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/ 




 

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#464693

On 06/15/2017 04:55 PM, John Larkin wrote:
> 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?

Suitably modified for NEMA 6P, for an extra $5k per unit. ;)

I really like those Hammond boxes with the metal mesh EMI gaskets.
Pricey though.

With that and good EMI shielding on the board, there are no SMPS spurs
visible above the dark noise, even on a spectrum analyzer with a 100-Hz
IF bandwidth.  Without the gaskets it isn't nearly as good, even though
the powder coating is masked off on the contact surfaces.

M1  BOX ALUM EXTRUDED EMI 120x103x32mm  MECH    1457L1201EBK
Hammond                 $32.14 @ qty 10

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

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#464700

On Fri, 16 Jun 2017 12:43:03 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 06/15/2017 04:55 PM, John Larkin wrote:
>> 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?
>
>Suitably modified for NEMA 6P, for an extra $5k per unit. ;)
>
>I really like those Hammond boxes with the metal mesh EMI gaskets.
>Pricey though.
>
>With that and good EMI shielding on the board, there are no SMPS spurs
>visible above the dark noise, even on a spectrum analyzer with a 100-Hz
>IF bandwidth.  Without the gaskets it isn't nearly as good, even though
>the powder coating is masked off on the contact surfaces.
>
>M1  BOX ALUM EXTRUDED EMI 120x103x32mm  MECH    1457L1201EBK
>Hammond                 $32.14 @ qty 10
>
>Cheers
>
>Phil Hobbs

I would have preferred a nice rectangular die-cast box with a screw
lid, but we don't have any handy. I guess I should order a few,
various sizes. Drilling and screwing stuff to the DBC can is sort of
flimsy. On the other hand, it solders nicely.





-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#464702

On 06/16/2017 01:11 PM, John Larkin wrote:
> On Fri, 16 Jun 2017 12:43:03 -0400, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
> 
>> On 06/15/2017 04:55 PM, John Larkin wrote:
>>> 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?
>>
>> Suitably modified for NEMA 6P, for an extra $5k per unit. ;)
>>
>> I really like those Hammond boxes with the metal mesh EMI gaskets.
>> Pricey though.
>>
>> With that and good EMI shielding on the board, there are no SMPS spurs
>> visible above the dark noise, even on a spectrum analyzer with a 100-Hz
>> IF bandwidth.  Without the gaskets it isn't nearly as good, even though
>> the powder coating is masked off on the contact surfaces.
>>
>> M1  BOX ALUM EXTRUDED EMI 120x103x32mm  MECH    1457L1201EBK
>> Hammond                 $32.14 @ qty 10n
>>
>> Cheers
>>
>> Phil Hobbs
> 
> I would have preferred a nice rectangular die-cast box with a screw
> lid, but we don't have any handy. I guess I should order a few,
> various sizes. Drilling and screwing stuff to the DBC can is sort of
> flimsy. On the other hand, it solders nicely.

My film cans solder well too.  I bought, like, 1000 pieces of a very
nice Russian 39 nF feedthrough caps, and use those for power and low
speed stuff.  They hold up well to slow soldering, too.

Cheers

Phil Hobbs
-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

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#464703

On Thu, 15 Jun 2017 13:55:48 -0700, John Larkin
<jjlarkin@highland_snip_technology.com> wrote:

>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.

Have you considered installing an RF screen room?  
<http://www.ets-lindgren.com/RFShieldedEnclosures>
We had an RF pollution problem at one company.  Only one bench (not
mine) needed screening, so we build an elevated wood frame, and
covered it with brass mesh wire screen.  The mesh was wide enough that
it didn't need its own HVAC system to prevent meltdown.  Add a brass
door frame, ordinary door covered with brass mesh, and finger stock
all around.  At another company, located next to SJO, we had a burnin
room that needed to limit the RF leakage towards the airport.  This
one was similar, but made of soldered brass sheet stock.  Expensive,
but quite good.  I have photos of these and others, somewhere, maybe.

There are also benchtop RF screen boxes:
<http://www.rfshieldbox.com>
<http://www.rfshieldbox.com/ramsey.html>

I needed one to tune up pagers on the same frequency as an active 500
watt paging transmitter about 1/4 mile away.  There was no money
available to buy something, so I hijacked an old environmental
chamber, added finger stock on the door, wire mesh over the window,
and filtering on the power, making a rather nice looking screen box.

For those occasions where a screen room or box are unavailable, I have
a sheet of aluminized mylar, which I convert into a tent of sorts.  It
was originally a high altitude balloon.  It has plenty of gaps to leak
RF, but it works reasonably.  I haven't tried it, but a space blanket
might work:
<https://www.google.com/search?q=space+blanket&tbm=isch>
<https://en.wikipedia.org/wiki/Space_blanket>

Another possible solution is to reduce the RF at the source.  What you
need is a supply of Orgonite delivered to the Sutro tower in a
ceremony called "gifting".
<http://www.awesomeorgonite.com/gifting.html>
<https://www.google.com/search?q=orgonite&tbm=isch>
The seller positively guarantees that if you dump some of these near
the base of the tower, they will "...diminish the harmful effects of
electromagnetic radiation, detoxify bodies of water and generally
enhance our environment".  There's no mention of fixing ingress and
noise problems, but if you ask, the seller will probably add it to
their list.


-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

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#464710

John Larkin wrote:


> 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.
> 
That's NOWHERE good enough!  You need a feedthrough cap there, too.  That 
wall-wart jack is the least suppressing port on the can, so most likely the 
primary way interference gets in.
> 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?
> 
> 
> 
Only if still filled with cookies.  Instruction booklet should indicate the 
end user needs to eat all the cookies before installing the electronics into 
the can.

Jon

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