It doesn't even have to be a solid sheet of metal, a grid with openings
sized for the lowest frequency you want to block will also work. See
also: the screen keeping all those microwaves in the oven where they
belong.
I used to work at a facility called "The Trestle" which was used to test
EMP effects on aircraft. The entire test site was completely surrounded
by a wire grid, designed to keep the EMP inside and not turn the city of
Albuquerque off when the EMP generators fired. I never saw any testing
but found a fun article.
http://www.chucksville.org/trestle.html
Eric Kalgren
Electrical Engineer
The Ferrite Co. Inc.
165 Ledge Street
Nashua, NH 03060
Phone 603-881-5234 X 153
Fax 603-881-5406
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge
Sent: Wednesday, June 16, 2010 1:53 PM
To: [log in to unmask]
Subject: Re: [TN] Pewter as RF screening material
Sure you can. Semding you a table with skin depth vs freq and also RF
resistivity for some common metals used in PWBs. Notice the
considerable
differencies. RF designers use to forget this.
Off line.
/Inge
--------------------------------------------------
From: "Eric CHRISTISON" <[log in to unmask]>
Sent: den 14 June 2010 16:43
To: <[log in to unmask]>
Subject: Re: [TN] Pewter as RF screening material
> "Speaking RF signals at radar levels, magnetrons,
> klystrons, TWTs and other high power sources, I would not use
pewter."
>
> You're talking of peak pulse powers in MW here aren't you?
>
> Can't you figure out a minimum thickness for any screening material
based
> on something like resistivity and loss tangent, it's called skin depth
or
> something?
>
>
>
>
>
> On 14/06/2010 15:18, Mike Fenner wrote:
>> Hmm....
>>
>> Some lead free solders are not a million miles from pewter.
>>
>> Regards
>>
>> Mike
>>
>>
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge
>> Sent: Thursday, June 10, 2010 7:01 AM
>> To: [log in to unmask]
>> Subject: Re: [TN] Pewter as RF screening material
>>
>> Hi Grant,
>>
>> any METAL case will work. What you create is a Faraday cage, that
will
>> eliminate electrostatic and electromagnetic influence. However, it
will
>> NOT
>>
>> eliminate static magnetic fields, nor low frequency electromagnetic
>> waves.
>> In such a case you'll need ferro materials, one of the best being so
>> called mu metal. But, as your question was about RF, pewter will
work,
>> not
>> as good as ferro materials, but it depends on the pewter wall
thickness.
>> In
>>
>> many modern electronics, you get acceptable RF shielding by means of
>> plastic
>>
>> boxes with a thin metal coating only. Works for weak RF signals,
which
>> are
>> often the case within commercial products like mobile telephones and
>> transistor radios. Speaking RF signals at radar levels, magnetrons,
>> klystrons, TWTs and other high power sources, I would not use
pewter.
>>
>> Inge
>>
>> --------------------------------------------------
>> From: "Grant Emandien"<[log in to unmask]>
>> Sent: den 9 June 2010 11:22
>> To:<[log in to unmask]>
>> Subject: [TN] Pewter as RF screening material
>>
>>
>>> Hi,
>>>
>>> Does anyone used lead-free pewter for RF screening purposes?
>>>
>>> Pros& Cons?
>>>
>>> Regards
>>> Grant
>>>
>>>
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>
> --
> Eric Christison Msc
> Mechanical Engineer
> Consumer& Micro group
> Imaging Division
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> STMicroelectronics (R&D) Ltd
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