Increasing the Range

   Increasing the range of a wireless network
is a lot easier said than done. There are many considerations
that one has to take into account.

    The first problem is that wireless signals
do not travel very well through obstructions. It is true,
that at close range a wireless signal will penetrate walls.
However, at longer distances a wireless signal can have problems
even getting through leaves.

   This is where line of sight comes into play.
If you can not see the point of wireless transmission,
then the wireless signal probably will not reach you.
You may have to trim some trees or construct an antenna tower
in order to get a clear line of sight to your transmission point.
However, this isn't really an option for someone, like me,
who lives in an apartment. Trust me! apartment complex management
doesn't take too kindly to you cutting down their trees.

    Direct line of sight obstructions are not the only problem.
Your transmission signal has a distinct three dimensional oval shape.
The area contained in this oval is called the Fresnel zone.
Unless you are an engineer, don't worry too much
about the specifics of the Fresnel zone.
All you need to know is that anything protruding
into this oval shaped area may affect your wireless signal.
It may not completely block your signal, but it can dramatically affect
the performance and speed of your connection. You can go to zytrax
for a more complete definition and a calculator to find the dimensions
of your Fresnel zone. If you really, really need to know
the specifics of the Fresnel Zone you can view Yibin Liang's masters thesis on the subject.

    Another thing to take into consideration is signal power.
The power of the signal emitted by your wireless device is measured in
dbm (decibels referenced to one milliwatt). The higher the dbm
the stronger the signal strength of your wireless device.
The signal strength of access points and routers is greater
than the strength of wireless cards.
So that to increase the range of a network one may have to increase
the signal strength at both ends of the network. There are basically
two ways to improve signal strength. One is to add an amplifier
to actually increase the power(dbm) of the signal. The problem
with amplifiers is that they are relatively expensive, and can not
easily be installed on a wireless card on a laptop. The other solution
is to add a larger antenna to your device. While this does not directly
increase the signal's power it does focus the signal more efficiently,
thus increasing the range. One problem here is that most wireless cards
do not have external connectors for an antenna.

   One can see that it is difficult to strengthen the signal
on the wireless card side. However, increasing the signal strength
of the router or access point also increases the reception sensitivity.
Therefore, they may be able to pick up the weaker signal
of the wireless card at longer distances.