Um, you're probably
right, but that study is even denser than the concrete they
used.
I'm sorry I should
have given a more specific reference. I meant a different study on the same web
page. It does have a table at the end that summarizes the
findings.
Stone,
W. C., "Electromagnetic
Signal Attenuation in Construction Materials," NISTIR 6055, pp.202. ,NIST
Construction Automation Program Report No. 3. October, 1997.
-----Original Message-----So, if I'm making any sense out of this document <http://www.bfrl.nist.gov/861/CMAG/publications/b96119.pdf> then, they say on page 6-10, that 500 mm of concrete wall gives -8 dB ???
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of S Woodside
Sent: Wednesday, June 18, 2003 10:45 PM
To: John Berry
Cc: [EMAIL PROTECTED]
Subject: Re: [BAWUG] concrete
It would be so much easier if there were a table somewhere, with different materials, thicknesses, and the dB of attenuation.
simon
On Wednesday, June 18, 2003, at 08:53 PM, John Berry wrote:
Concrete will attenuate the signal and four feet is a lot of concrete. You can check the NIST tests from 1996 for reference. They tested many construction materials including concrete with and without rebar. Generally attenuation increases with density, though rebar alone will kill just about any signal.
http://www.bfrl.nist.gov/861/CMAG/publications/
--Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of S Woodside
Sent: Wednesday, June 18, 2003 2:00 PM
To: [EMAIL PROTECTED]
Cc: 'Richard Buckley'; [EMAIL PROTECTED]
Subject: Re: [BAWUG] concrete
Concrete is (relatively) irrelevant, it's the metal content that matters. If the walls are just cinderblock, that's not so bad, but if they're rebar (i.e., reinforced concrete with metal bars) then you probably won't be able to get through, it's a faraday shield.
And by the way, many/most modern concrete buildings are made of rebar for the floors at a minimum, the walls might be cinderblock though?
simon
On Wednesday, June 18, 2003, at 04:32 PM, <[EMAIL PROTECTED]> wrote:
Hi folks
We are working in a concrete building with thick concrete floors and walls and we need to go through approx. 4feet of concrete at a distance of 150 feet. We are using a Lynksys 54g access point and 9db antenna being picked up by a WMP54G Wireless PCI LAN Adapter. It is not working for us at the moment, do we need to use a stronger antenna to pick up the signal or will any signal get through 4 feet of concrete at all?
I have seen only one thread in the recent past dealing with the thickness of concrete where someone stated that "
driving a 12cm wave through a couple meters of concrete and steel doesn't
work that well..."
Any thoughts on it would be greatly appreciated
Kind Regards
Oliver Dempsey
phone: 00353 502 26263
mobile: 00353 86 8219430
--
www.simonwoodside.com -- 99% Devil, 1% Angel
--
www.simonwoodside.com -- 99% Devil, 1% Angel
