[TowerTalk] Faraday Cage

[Gene Smar]

TT:

     Here's some info on mil- and intel-quality shielded rooms: http://www.ramayes.com/Shield_Room_FAQ.htm .  Check out the tabs along the bottom of the page for details on things like 60 Hz AC filters and air vent waveguides.  Plumbing is another matter as well.  I've been in these things (can't tell you where) and you'd better not be claustrophobic to work in 'em.


73 de
Gene Smar  AD3F


  From: warrenwolff at aol.com
Date: 2008/06/01 Sun PM 01:03:25 EDT
To: xdavid at cis-broadband.com, sanorm at columbus.rr.com
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Faraday Cage

Hi again folks,

Wow, I surely do stir up a hornet's nest when I pose some of my 
questions to this group.

This subject of a Faraday?Shielded Room came up when I was
trying to get this new house as protected as possible.? The almighty
dollar interfered with some of my thoughts, this being one of them.

I was suspecting that a bit less than 1/4 wave at 2 meters would have
been sufficient for such a room.

Now David has dug up a reference:


- Aperture
Aperture
An opening in a shielded enclosure that may become the source of leakage for electromagnetic energy. This is

most common in joints, seams and penetrations such as switches, connectors, and lamps/LEDs. Typically, the

maximum dimension of an aperture should be less than 1/20 wavelength of the highest frequency of interest in

order to avoid emissions.

Interesting, to say the least.

The comments re: air conditioning resurrected an old experience(s).? When I was an OIC of a STRATCOM
Receiver Site in Hawaii, we had a all copper screen room.? As Program Manager of a Comm System in
Kuwait, we also had one.? In both cases, we did not close the door unless absolutely necessary because
of poor air conditioning.

Then it hit me; my project engineer from USAF days has a PhD in Physics.? Think I will
ask him if 1/20 or 1/10 is overkill.? The idea of something less than the tightly closed
copper mesh room still intrigues me - - IF the spacing is not too small.? Doorways and
A/C ducts probably pose the biggest problem to a "cheapo" room.

I appreciate all of the interest and the well-founded references provided so far.

Warren; W7WY




_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk