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

[John Ferrell]

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

  ----- Original Message ----- 
  From: Bob Richards 
  To: 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.


  Bill Glaze <billglaze at triad.rr.com> wrote:
    Bob:
    Do I recall when such a room as you describe was known as a "Faraday Cage?"  Or am I having one of RvP's "Senior Moments?"  (No offense, Ron! O:-) ) 
    Bill Glaze

    Bob Richards wrote:

      The ideal material I have seen is used in RF shielded room walls. It is 3/4" high-density particle board, skinned with galvanized steel on both sides, maybe 28ga. Very flat, and very smooth. It will bow just a little, maybe 1/2 inch at the most, when you pick it up from the end. Came in 4' x 12' as I recall. Don't have any idea where you could purchase it at a reasonable cost. I was hoping they would have a sheet of it leftover when they built one of the chambers where I used to work, but they didn't.

      Bob Richards.


      John Ferrell <johnferrell at earthlink.net> wrote:
        The test for a Pool Table is to put a straight edge across it and try to slide a dollar bill under it.

        BTW, I am surprised to hear the talk about using pins. One of the first things Dave Guerin taught me was to use masking tape instead!

        John Ferrell   
        My Competition is not my enemy! 
        http://DixieNC.US

          ----- Original Message ----- 
          From: Mark Grabowski 
          To: 'discussion at nsrca.org' 
          Sent: Friday, November 19, 2004 11:21 AM
          Subject: Measuring Surface Flatness (was "Cabinet Grade Particle Board")


          We've seen some great ideas from several folks. However, a common element to this discussion is that you need to measure how flat the surface winds up. What tricks are you guys using to actually measure how flat the surface is of the bench you just built?





  Bob Richards
  bob at toprudder.com
  http://www.toprudder.com
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