Signal doesn't pass through a short or thin wall
Range is highly dependent on the physical environment. In a line-of-sight location, with elevated
and calibrated antennas, range predictions are quite accurate. This is not true in a “typical” office
building, where the walls may be simple drywall (which is almost transparent to microwaves), or
could be plaster with metal underneath. Most sites are somewhere between these two extremes,
and consist of a mixture of surfaces. You can’t tell what is inside a wall by just looking at it, and
we can’t tell you exactly what distance you will achieve. Consider published range information to
be typical, average, common or usual. Do not expect it to be exact.
Signal strength drops when a cell phone is used in the area
Range also depends on the electronic environment. If other equipment that could cause
interference is nearby, the range of your transceiver could vary widely, and could change
suddenly when the other equipment activates. This is particularly true for 802.11b installations,
which share their frequencies with microwave ovens, cordless phones, wireless hi-fi speakers,
electronics toys and similar devices. Try to keep your system away from other transmitters, and
from other sources of electrical noise, such as large motors, spot welders, and similar
“electronically noisy” devices.
Range is shorter than it should be
Repeat some tests late in the evening, or on a weekend, when there may be less interference.
However, some users leave their networks turned all the time so this test is not foolproof. By all
means, try more than one channel. Your range problem may just be a nearby user whose system
uses your present test channel.
Interference from fluorescent lights
If you mount an access point close to fluorescent light fixtures, the lamp glow appears constant,
but inside the lamp tube, ionization appears and disappears 120 times a second. This can
modulate or “chop” an incoming signal and interfere with reception.
When too much range is undesirable
Too much range is not necessarily a good thing. At first it would appear that you would want as
much range as possible, but with the increase in range comes an increase in interference
potential, as your unit hears not only your other units but also manages to hear the systems of
other companies up and down the street. If you have a large installation, you will also wind up
with more than one access point using the same channel. If a remote unit hears two or more
access points, this will slow the network network.
Prevent access to wireless networks from outside the building
Excess
transmit
range presents a special reverse problem. For example, putting an access point
adjacent to a second floor bay window invites anyone with the right software on the street below
to pick up and enjoy all network transmissions. We discuss some possible solutions to this
problem further on.
Problems with Network Connectivity
If you cannot connect to the wireless network, try the following:
