[Hidden-tech] Sharing wifi between apartments

[Kevin Phillips]

So to sum up what Jim is saying, try the $40 Netgear wireless router from
Staples and see how it goes !!!

Kevin Phillips 
KPIT Computer Consulting 
kevin at kpitconsulting.com 
Office (413) 420-0212
Cell (413) 330-7789

www.kpitconsulting.com
www.wmassforums.com


-----Original Message-----
From: hidden-discuss-bounces at lists.hidden-tech.net
[mailto:hidden-discuss-bounces at lists.hidden-tech.net] On Behalf Of
ussailis at shaysnet.com
Sent: Monday, January 10, 2011 6:47 PM
To: sreed at avacoda.com; hidden-discuss at lists.hidden-tech.net
Subject: Re: [Hidden-tech] Sharing wifi between apartments

   ** Be sure to fill out the survey/skills inventory in the member's area.
   ** If you did, we all thank you.


>From the radio standpoint there are a few issues that usually can be
overcome.

1. Use the slowest speed WiFi signal that you find. Contrary to popular
opinion, faster speeds require more radio bandwidth, which requires more
power to achieve the same signal level at any given remote point. 

If 802.11b operating at 1 Mb /s provides a range of 100 feet, then, all
things equal, 802.11b operating at 11 Mb / s will provide a range of
roughly 35 feet.

Worse the 802.11 flavor that runs at 100 Mb / s will provide a range of 10
feet.

The good news is most access points / wireless routers have a circuit that
automatically backs off on speed as the signal gets weaker.

{as an aside, does it make sense to have a 100 Mb / s router when DSL is
under 1 Mb / s?}

2. Get the most powerful router you can find. Several years ago Senao
offered one that ran 200 mW (milliwatts). In North America one watt is the
legal maximum for normal installations. Not so in Europe, where it is 0.1
Watt (100 mW). Most routers run 100 mW so they can be approved everywhere.

When you set up your router, if you are offered a choice, ALWAYS set the
service location to USA. This set-up action often changes the power output. 

3. Consider a "repeater." Often these gadgets run a power output closer to
one watt, since their purpose is to increase range. Look for one that is
only permitted for sale in the US or Canada.

4. A lower frequency will give more range. Almost all 802.11 devices
operate in the 2.45 GHz band. 802.11a operates in the 5 GHz band. There is
no reason to prevent a manufacturer from making a WiFi router in the 900
MHz band.

So all things equal, a 900 MHz router will have more range (and be slightly
less bothered by multipath signals). You will probably only find 2.45 GHz
and 5 GHz units, tho.

The 5 GHz version tends to be designed for campus facilities, so more power
is usually offered. Check this. You will need twice the power in an 802.11a
router to be equal with an 802.11b router.

5. Antennas. You can get an antenna with more gain. BUT, all antenna gain
comes from the "beaming" of the signal towards one direction at the expense
of other directions. Such directionality might work in some situations, not
work in others.

Also be careful of the BS factors with regard to antenna gains. The gain
may be far from true. Extra fancy "elements" might be added to the antenna
just to catch the eye of the owner. (very common in TV antennas).

6. Multiple antennas on the router. This is a common device to improve
signal strength when signals are traveling by two or more paths
(multipath). If it is implemented properly, it works. The antenna with the
better signal is selected for a given set of conditions. 

The selection of both antennas at all times doesn't work. 

Good implementations existed when the WiFi components were made in the USA.
I don't see that anymore.

7. Finally, the building can be an issue.

If the building is newish, check the sheetrock. There is a metal backed
sheetrock that was common in apartment buildings built about 25 years ago.
It might still be used, and in some places it might be code. Don't expect a
WiFi signal to go far in this building.

Then there can also be metal studs in the walls even if non-metal backed
sheetrock is used. This will attenuate WiFi signals a very small amount. It
is much more of a problem with FM radio signals.

Some 19th century buildings were built with rock. If this is the case, you
will want to evaluate WiFi transmission thru the walls before you spend a
lot on components.

The same goes for converted mill buildings. At 221 Pine St in Florence, for
example, I found that transmissions thru some parts of the building were
good for 60 feet or more. Other parts were worse, far worse. That building
was constructed in several stages over the years. Some interior walls are
wood, some brick, some concrete. Some floors are wood, others concrete with
rebar. 

Concrete with rebar is not good for WiFi transmission. 


Jim Ussailis
jim at nationalwireless.com


Original Message:
-----------------
From: Scott Reed sreed at avacoda.com
Date: Mon, 10 Jan 2011 10:23:57 -0500
To: Hidden-discuss at lists.hidden-tech.net
Subject: [Hidden-tech] Sharing wifi between apartments


   ** Be sure to fill out the survey/skills inventory in the member's area.
   ** If you did, we all thank you.


A friend asked me for advice about using wifi to share an internet
connection among a group of apartment dwellers. Does anyone have
experience or advice? Is it possible without wires except in the unit
with the internet service? What kind of equipment is required?
Thanks,
  Scott
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