Wifi range

[chandrika]

With regards to a wifi signal. I was wondering how a brick wall might attenuate/reduce the signals range. Say for example using an omni antenna that has a normal range of 50meter on 2.4GHz if it was inside a brick walled and plastered room, what the range would be outside the room.

Would it reduce it by half, or is there any way to estimate how much a plastered brick wall would reduce a signal by?

If I had a wifi enabled phone I could go for a walk and check for myself...but i dont have one, so just wondered if anyone could guesstimate....

As I understand it a glass window doesnt reduce a signal at all, but brickwork and plaster might do.

[deepsand]

While GSM signals are little affected by such, Wi-Fi is more highly susceptible to attenuation and reflection owing to the carbon content in plaster, brick, and mortar. It is not possible to know how much of such might be experienced with your particular building materials.

A quick reading of HIGH FREQUENCY SIGNAL ATTENUATION THROUGH MATERIALS (http://but.unitbv.ro/BU2009/BULETIN2009/Series%20I/BULETIN%20I%20PDF/Electrical%20Engineering,%20Electronics%20and%20Au tomatics/Scutaru%20M_09.pdf) suggest that attenuation might be on the order of 6-11 dBm. That's a drop in power to roughly 1/4 to 1/16 of that of the original signal.

[edhan]

As far as I know, it is depending on the wall that comes with the iron rods inside that will cause the reduction of the signals. I might be wrong but so far I have tested for houses that come with 2 - 3 storey high and not problem with the signal. I have used the detector to check the wall for iron rods but the houses seem to have less of those rods.

[deepsand]

Homes here are generally framed with wood; the only metallic objects contained within the frame are plumbing runs(copper,) electrical runs (copper wire, occasionally within steel runs,) and central heat/air ducts (generally zinc galvanized tin.) None of these exist in sufficient amounts and concentrations to result in substantial attenuation or reflection.

However, many have batted insulation between the studs, which is covered on one side with a foil moisture barrier, and which can lead to both attenuation and reflection.

Earth based materials, such as plaster, mortar and brick contain high amounts of carbon in mineral form, which alone is an electrical conductor with a relatively low impedance; but, in the admixtures here involved, results in a composite with very high impedance that is susceptible to electromagnetic radiation at certain wavelengths.

[simonm]

My experience, traditional British build with internal brick walls and wood floors on joists.

The main single aerial wifi point is upstairs centre of house. The attenuation from the floors is negligible, with one wall (double brick thickness), I still get a decent signal, two walls and the signal isn't usable.

Also, don't forget your own body! If I have a single wall blocking the signal and I sit between signal and laptop, my overall signal is unusable. If I reposition so I am facing laptop and wifi point I'm back in business!

[deepsand]

Also, don't forget your own body! If I have a single wall blocking the signal and I sit between signal and laptop, my overall signal is unusable.
You've just discovered a detector for carbon based life forms! :D

[Bernd]

As I understand it a glass window doesnt reduce a signal at all, but brickwork and plaster might do.Every material will reduce the signal. It depends on the kind of material and its thickness how much the reduction is.

[chandrika]

Thanks...

Also with regards the field of radiation, the signal bubble that is being transmitted from the omni antenna, where does the bubble radiate from? Would the antenna be at the center of that bubble, or is that 50meter radius bubble transmitted from the end of the antenna so reaching 100meter from its tip?

would it be like this....

http://www.findallsorts.com/antenna1.jpg


or like this

http://www.findallsorts.com/antenna2.jpg

[Bernd]

The whole antenna is in the middle of the electromagnetic filed, no disturbances presupposed.
A little animation (http://de.wikipedia.org/w/index.php?title=Datei:Dipolentstehung.gif&filetimestamp=20071208093526).

[wige]

The signal is transmitted from the entire height of the antenna, as a wave or pulse - imagine throwing a stick in a calm lake or pond, you get waves in every direction, but wider along the length of the stick. So, it would be something like this: {{{{{|}}}}} emanating from the antenna.

In tech support, the general rule of thumb was that an interior wall would diminish the remaining range by 1/2, and an exterior wall would diminish the remaining range by 3/4. So, if you have a router with a range of 100 yards, and a wall 50 yards away, the theoretical range would be about 25 yards beyond the interior wall, or 13 yards beyond an external wall.

[deepsand]

See Attenuation Properties of Common Building Materials at Wi-Fi - Wireless Wiki (http://wireless.wikia.com/wiki/Wi-Fi) .

For antenna info., see 3Com Wireless Antennas Product Guide (http://www.3com.com/other/pdfs/products/en_US/101900.pdf)

[chandrika]

Thanks very much for all the useful info, :D

[SusanMart]

and is there a way to enlarge the internet zonefrom the antheme on more than 100 meters?

or it's the deal of the FUture?

[allisonays]

I think it is more of the attenuation that will affect the wifi signal, the farther you go the lesser signal you can have.. I dont have much idea with the effect of walls on wifi signal, can someone give me a site that will explain everything regarding interruption of walls on wifi signal. Thanks..

[chandrika]

I think it is more of the attenuation that will affect the wifi signal, the farther you go the lesser signal you can have.. I dont have much idea with the effect of walls on wifi signal, can someone give me a site that will explain everything regarding interruption of walls on wifi signal. Thanks..

the link Deepsand put has that info


See Attenuation Properties of Common Building Materials at Wi-Fi - Wireless Wiki (http://wireless.wikia.com/wiki/Wi-Fi) .

[deepsand]

and is there a way to enlarge the internet zonefrom the antheme on more than 100 meters?
Only with a substantial increase in transmitter power and/or repeaters.

Not only is the first costly, but regulated, so as to reduce interference between transmitters.

[SusanMart]

Only with a substantial increase in transmitter power and/or repeaters.

Not only is the first costly, but regulated, so as to reduce interference between transmitters.

thank you!
can it be also particially a commercial issue?
Because 100 meters limit is a LIMIT and the more there are wifi zones, the more the "owners" earn money?

[deepsand]

Aside from power, and the avoidance of interference, the only other issues relate to technical factors involving the media, modulation method, and frequency/ wavelength employed.

The Laws of Physics dictate an upper limit of the amount of useful information that can be carried within a given bandwidth. These are the same Laws that limit the effective transmission speeds of dial-up, DSL, and fiber optic connections.

See Shannon-Hartley theorem - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Shannon-Hartley_theorem) .

[TrafficProducer]

There are ways to boost the signal, mainly by using shaped foil to reflect signals in the direction you need, these can be purchased or make one yourself easy.

I have a couple of video's how Do It Yourself to here (http://www.acomputerportal.com/wap_wml_wi_fi.html#WiFi)

[TrafficProducer]

Opps!!! WPW is playing Up

[leanback]

Ok All, I'm still reading.... This could really be a great ebook subject...
A durrrrrrr on my part.

Thanks for info,
Love this site

[zippock]

I do not use wifi, because I am afraid to be bald... really, it has an influence!

[pixelbob]

If your house has many wall partition, it is advisable to use a repeater. Here is a simple rule regarding WiFi, 1 wall partition is equivalent to -10 meters of the WiFi range. You may also check your WiFi settings, check if it is set to "infrastructure mode" this will improve the reach of your WiFi signal.