Installation Instructions

F-2

Cisco Aironet Wireless LAN Client Adapters Installation and Configuration Guide for Windows

OL-1394-06

Appendix F Performing a Site Survey

Overview

Note This appendix applies only to people who are responsible for conducting a site survey to determine the

best placement of infrastructure devices within a wireless network.

ACU’s site survey tool can assist you in conducting a site survey. The tool operates at the RF level and

is used to determine the best placement and coverage (overlap) for your network’s infrastructure devices.

During a site survey, the current status of the network is read from the client adapter and displayed four

times per second so you can accurately gauge network performance. The feedback that you receive can

help you to eliminate areas of low RF signal levels that can result in a loss of connection between the

client adapter and its associated access point (or other infrastructure device).

The site survey tool can be operated in two modes:

• Passive Mode—This is the default site survey mode. It does not initiate any RF network traffic; it

simply listens to the traffic that the client adapter hears and displays the results. Follow the

instructions in the “Using Passive Mode” section on page F-3 to activate the passive mode.

• Active Mode—This mode causes the client adapter to actively send or receive low-level RF packets

to or from its associated access point and provides information on the success rate. It also enables

you to set parameters governing how the site survey is performed (such as the data rate). Follow the

instructions in the “Using Active Mode” section on page F-7 to activate the active mode.

Guidelines

Keep the following guidelines in mind when preparing to perform a site survey:

• Perform the site survey when the RF link is functioning with all other systems and noise sources

operational.

• Execute the site survey entirely from the mobile station.

• When using the active mode, conduct the site survey with all variables set to operational values.

Additional Information

Also consider the following operating and environmental conditions when performing a site survey:

• Data rates—Sensitivity and range are inversely proportional to data bit rates. Therefore, the

maximum radio range is achieved at the lowest workable data rate, and a decrease in receiver

threshold sensitivity occurs as the radio data increases.

• Antenna type and placement—Proper antenna configuration is a critical factor in maximizing

radio range. As a general rule, range increases in proportion to antenna height.

• Physical environment—Clear or open areas provide better radio range than closed or filled areas.

Also, the less cluttered the work environment, the greater the range.