Measuring Surface Flatness (was "Cabinet Grade Particle Board")

[Rcmaster199 at aol.com]

The tangents that some threads create are often much more interesting than  
the original intent of the thread. 
 
Keith I would say it's not a good idea. If you built a fuse out of this  
material, (done everyday BTW),  I suggest you build it large enough to  accomodate 
the person flying it (vbg). I know Bill, Don Ramsey and Al Glenn and  
probably several more, flew or still fly "Faraday Cages" for a living
 
Now, how we went from measuring surface flatness to "shielding" devices  from 
EMI/RFI (regardless of what the emitting source is), is beyond me
 
MattK
 
In a message dated 11/23/2004 4:32:15 PM Eastern Standard Time,  
tkeithb at comcast.net writes:

In other words, if you built your fuse out of  this material you'd probably 
want to run your antenna externally.  ;-)
 
 
----- Original Message ----- 

From:  _Bob  Richards_ (mailto:bob at toprudder.com)  
To: _discussion at nsrca.org_ (mailto:discussion at nsrca.org)  
Sent: Tuesday, November 23, 2004 2:59  PM
Subject: Re: Measuring Surface Flatness  (was "Cabinet Grade Particle Board")


John,
 
I disagree. The definition of a "Faraday CAGE",  which is what Bill said, is 
a completely conductive sealed enclosure.
 
Also, the edges don't have to be fully bonded together for RF  protection. 
They can be stitched together at intervals depending on how high  in frequency 
you want attenuation. The closer the spacing, the higher the  cutoff frequency. 
Obviously, if you want cutoff up into the gigahertz range,  you pretty much 
need a continuous bond.
 
_http://www.boltlightningprotection.com/Elemental_Faraday_Cage.htm_ 
(http://www.boltlightningprotection.com/Elemental_Faraday_Cage.htm) 
 
_http://en.wikipedia.org/wiki/Faraday_cage_ 
(http://en.wikipedia.org/wiki/Faraday_cage) 
 
Bob.


John Ferrell <johnferrell at earthlink.net>  wrote:

Sorry to get picky, but a Faraday shield is  not an electromagnetic field, it 
is an electrostatic shield. 
 
An rf tight room needs the edges fully bonded  together and a Faraday shield 
requires that they be insulated.  

I think everyone knows what is being said,  but I felt obliged to add the 
detail. 
 
John Ferrell   
My Competition is not my enemy! 
_http://DixieNC.US_ (http://dixienc.us/) 


----- Original Message ----- 
From:  _Bob  Richards_ (mailto:bob at toprudder.com)  
To: _discussion at nsrca.org_ (mailto:discussion at nsrca.org)  
Sent: Monday, November 22, 2004  1:06 PM
Subject: Re: Measuring Surface  Flatness (was "Cabinet Grade Particle Board")


That's what it is. No RF gets in or out. Something like 110dB  attenuation.
 
Bob.






 
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