Chris,

Attenuation of RF signal at 2.4 GHz through buildings is huge! Not to
mention the flea power on WiFi.  You probably won't get through the building
but you can always try.  Not everything follows the expected rules in RF.
That being said, think of an antenna no different than that of a optical
lens on a light.  It focuses the energy.  To get a lot of gain you give up
something.  On a high gain vertical omnidirectional antenna the energy is
forced into a doughnut shape sending the signal on a straight plane towards
the horizon. Very little energy goes below or above the antenna.  This is
why people directly under a high gain antenna have a harder time connecting
or staying connected.  There is no RF saturation.  People further away do
better.  On a directional antenna the energy is focused like a flashlight or
headlight.  The higher the gain, the more focused the RF energy becomes.
This would be like focusing a flashlight to almost a laser beam.  This is
called beamwidth in an antenna and is measured in degrees. The higher the
gain the smaller the beamwidth in degrees.   Enough of the RF and Antenna
lesson.

This beamwidth can work in your favor.  If you can find a dependable hard
surface to point your antenna at and bounce off the surface from B to A
(like a laser beam on a mirror) you may solve your problem.  You may still
experience multipath distortions.

Sometimes you just experiment and it works,  then you figure out why and
document it for future use.  Then you write a paper and get a Nobel prize!

What is your minimum speed?  Yes, I said speed not bandwidth. Are there no
other options? VPN?  Point to point T1 or nonloaded DSL (or just the
cheapest way to get one pair of dead copper from point A to point B)  and an
in-house DSL extender? Fiber to the roof or around to the other side of the
building and then an integrated WiFi enterprise panel antenna pointing in
the correct direction? Just some thoughts.

Good Luck,

S. Earl Jarosh,  N0HZ
Cell:   612-868-1313
Off:    763-545-3275
Fax:   763-546-0027
Money Centers of America
V.P. of Information Technology
earl at jarosh.org
earljarosh at moneycenters.com
www.moneycenters.com



----- Original Message -----
From: "Chris Scheidecker" <scheides at iexposure.com>
To: <tcwug-list at tcwug.org>
Sent: Tuesday, December 16, 2003 6:35 PM
Subject: [TCWUG] Connectivity Distance


> How far will a 14dbi directional antenna reach?
>
> We're trying to get users at location B to connect to a base station at
> location A reliably.  Location A is one block from location B.  The access
> point (and the antenna) would be located in a window on the third floor of
> location or on the roof (still just over the third floor) of location A.
> Tough part is, location B is on the back side of a 3 - 4 story building.
>
> Assuming the walls of the building are not made of lead, what are the
chances
> of a reliable connection?
>
> Is 14dbi overkill?  Underkill?
>
> -Chris
>
> --
> Chris Scheidecker
> Associate Systems Administrator
> cscheidecker at iexposure.com
> Internet Exposure, Inc.
> http://www.iexposure.com
>
> 612.676.1946 x33
> Web Development-Web Marketing-ISP Services
> ------------------------------------------
>
>
> _______________________________________________
> Twin Cities Wireless Users Group Mailing List - Minneapolis/St. Paul,
Minnesota
> http://www.tcwug.org
> tcwug-list at tcwug.org
> https://mailman.real-time.com/mailman/listinfo/tcwug-list
>


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