56 RF Throughput, Performance and Troubleshooting
MX2 Reference Guide E-EQ-MX2RG-L-ARC
Site Survey
Many companies have an existing Ethernet or wired LAN infrastructure and want to be able to
extend that capability to wireless nodes. This is accomplished by attaching an access point to the
wired LAN, allowing the wireless clients to access the network resources.
MX2s, like other 386-compatible DOS computers, can be connected to networks. With RF
models, radio signals between the MX2s and the AP replace the wires connecting the nodes to the
network.
A site survey is an important part of setting up a wireless network. Contact your LXE
representative.
For most office environments, a site survey is not necessary. For large, industrial environments
requiring multiple APs, however, you should perform a site survey before installing a
RangeLAN2 network system. Run Proxim’s RL2SETUP.EXE
program on a laptop using a
RangeLAN2 card.
The purpose of a site survey is to calculate the most effective number of access points at a site and
the best placement and positioning of antennas for optimal reception of radio signals. This is done
by identifying areas where transmission failures occur. As each site is unique, the surveyor needs
to consider the exact conditions, as they will appear in the final installation. In addition to such
climate factors as moisture, excessive heat, and dust, a site survey can also be affected by physical
obstructions and electromagnetic interference. Also important is the identification of potential
cabling, connector, or power problems.
Throughput and Performance
The bandwidth on a radio network is constant for a given network. Therefore, the more active RF
units using the same frequency- hopping pattern, the slower the throughput of any one unit. If this
is a problem, you should install additional access points.
Radio signals may reflect off some obstacles and be absorbed by others. An RF unit with an
unobstructed line of sight to the access point antenna can successfully transmit and receive signals
at distances up to 1000 feet. In an environment that includes such obstructions as cubicle walls
typically used in modern offices, the range is reduced significantly, with a maximum distance of
500 feet. Where signals must penetrate office walls, the maximum distance may be only 300 feet.
Many other factors also affect performance of wireless LANs, including the following:
• Transmitter power
• Receiver sensitivity
• Interference caused by noise, receiver desensitization, spurious responses, and
intermodulation
• Shadowing
• Multipath fading
• Consumer products in use in the coverage area
Some of these factors can be sensed during a site survey and be avoided.
