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Tip of the Month

March 2003

Wireless Signal Strength

Analyzing the wireless signal strength in your wireless network is important to perform effective site surveys and to monitor the availability of your access points.

Before you begin to analyze signal strength, there are important considerations. Theoretically a signal from an Access Point would be a donut shape. The first factor we must consider is the antenna. Different antennae have different signal patterns. The next factor is the space where the Access Point is placed. Windows do little to block a signal, however a dividing wall made of concrete blocks with steel poles inside will severely degrade the signal. However, if the afternoon sun encourages all of the people on one side of the building to pull down their metal blinds, this could create an interesting signal blocking and reflecting environment. These factors will affect the signal strength that reaches the different spaces in your environment.

In order to analyze the signal strength in your environment, within AiroPeek and AiroPeek NX there is an icon resembling an antenna in the tool bar that will graphically display signal strength. You may also chose to show text-based information instead of graphical data. By selecting Tools/ Options/ 802.11/ Scan and clicking on Scanning Options you may scan Channels 1-14. Alternatively you may click on only applicable channels and choose the time to scan each channel. The time is listed, though you may also type in a zero ‘0’ and scan all applicable channels as quickly as possible.

By utilizing AiroPeek NX in this manner you will be able to develop a functional site survey map that will be the basis for Access Point placement as well as perform long term monitoring of the availability of those Access Points.

For more information about signal strength dynamics, read the “Converting Signal Strength Percentage to dBm Values” white paper written by WildPackets’ resident expert in wireless networking, Joe Bardwell, available from our White Papers Page. For those interested in becoming a wireless expert in their own right should check out information on WildPackets Academy’s wireless network analysis courses.