Do gas-filled windows block wireless signal?
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From: Jeff Liebermann on 28 Jun 2010 20:37 On Mon, 28 Jun 2010 17:11:23 -0400, "Don Phillipson" <e925(a)SPAMBLOCK.ncf.ca> wrote: >The engineer said he had never heard of either window structure >(aluminum here with steel magnets that hold the fly screens in place) >or gas-filled sealed panes obstructing wireless signals. Has anyone else? The glass probably has a low-emissivity TiN (Titanium Nitride) coating. That's about 35 ohms per square sheet resistance, which is as good as a dead short at RF frequencies. <http://802.11junk.com/jeffl/crud/Low-E-titanium-nitide-glass.pdf> (422 KBytes) Although the tests did not extend to RF frequencies, a look at Fig 4 shows that TiN transmission is totally blocked (<5%) at wavelengths longer than 3000nm. Is the fly screen made of aluminum or fiberglass? You might try the same test (open/closed window) with a cell phone. You'll probably see the same drop in signal level. -- Jeff Liebermann jeffl(a)cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
From: na6t on 1 Jul 2010 01:41 On Mon, 28 Jun 2010 17:11:23 -0400, "Don Phillipson" <e925(a)SPAMBLOCK.ncf.ca> wrote: >Wireless broadband was always marginal here (at least one >mile from the tower, with trees in the line of sight ) and became >impossible the day the windows were replaced with modern >"Energy Star" units, double-pane sealed units filled with gas >(either argon or krypton, I forget which.) I could not be sure of >the cause, but managed to reach an ISP engineer. One of his >suggestions was to try the directional wireless modem at an open >window, i.e. no glass -- which immediately provided a satisfactory >signal. I have instructions for various tests thus will quantify the >difference if I can. > >The engineer said he had never heard of either window structure >(aluminum here with steel magnets that hold the fly screens in place) >or gas-filled sealed panes obstructing wireless signals. Has anyone else? I've been building Wireless ISP's and installing wireless for about 10 years commercially. I've had numerous times that the client had tinted glass on an outside window, could see the wireless access point from the window and couldn't connect with a laptop because of the glass tinting. Open the window and the connect happens. Other times the window has a metal screen, great to keep the bugs out and the let in the air, but hell on Wireless, it act like a shield. On other problem with laptops is that the radio is mounted inside the laptop body beneath the keyboard. The antenna points down at the table the laptop is sitting on. sometimes by holding the laptop up and pointing the bottom of the laptop at the access point you can get a connect also. oh, Hi Jeff, it's been a while, Gud luck, Bob Robert Smith Consulting
From: Jeff Liebermann on 2 Jul 2010 01:45
On Wed, 30 Jun 2010 22:41:20 -0700, na6t(a)na6t.com wrote: >I've been building Wireless ISP's and installing wireless for about 10 >years commercially. Permit me to offer my sympathies. I lasted about 8 years and gave up. >Other times the window has a metal screen, great to keep the bugs out >and the let in the air, but hell on Wireless, it act like a shield. I've replaced those with fiberglass bug screening. Unlike aluminum, it does not corrode, dent, or unravel. Unfortunately, it will not support a small cat with sharp claws. >On other problem with laptops is that the radio is mounted inside the >laptop body beneath the keyboard. I haven't seen too many of those. When wireless cards were retrofited into existing models, some IBM Thinkpads and Compaq Presario laptops were installed with antennas under the keyboard. That went away with the next model. My favorite is Compaq cramming the antenna on the laptop hinge: <http://802.11junk.com/jeffl/antennas/laptops/slides/compaq-2120us.html> Not only did it not work very well, but the coax also tended to get crunched in the hinge. >oh, Hi Jeff, it's been a while, Hello. I was wondering where you've been hiding. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 # http://802.11junk.com jeffl(a)cruzio.com # http://www.LearnByDestroying.com AE6KS |