[sdiy] case shielding properties

[Tim Parkhurst]

Hi Mark,

As a mechanical designer, I would have to go with the steel for the best
shielding properties, followed by the thick aluminum and then the thin
aluminum. Some other factors will influence the 'quality' of the shield
(rectangular is better than square, use fewer parallel surfaces, round
openings are better than squared-off openings, etc.), but if you look at the
material used in RFI shielding you will find a lot of beryllium-copper,
plated copper, nickel-steel, or steel with various platings, and brass with
various platings. Aluminum is rarely, if ever, used for shielding purposes.
Unfortunately, most of the shielding materials I mentioned above are not
suitable for making enclosures, but given the choice between steel and
aluminum, I'd have to go with steel. 

Another choice would be an aluminum case with internal shields made of thin
steel, copper, or brass. I've done this quite a bit for RF amplifiers,
receivers and the like (I've designed enclosures for a lot of gear like
this). This is a very common industry practice.

Hope this helps!


Tim (designing kind o' guy) Servo
"Imagination is more important than knowledge." - Albert Einstein

***************************************
> -----Original Message-----
> From: mark s [mailto:djarum11 at mindspring.com]
> Sent: Thursday, May 27, 2004 2:37 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] case shielding properties
> 
> which offers better shielding properties, those thick die-cast aluminum
> alloy (380) boxes, a thinner finished-aluminum .040" box such as the LMK
> Crown Royal series, or a typical steel 19" rackmount box ?
> 
> thanks
> mark
> 
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