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Site Survey Tool - TamoGraph

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Introduction
Overview
System Requirements
Driver Installation
Licensing and Trial Version Limitations
Interface Overview
Access Point List
Floor Plan / Site Map
Plans and Surveys, Properties, and Options Panel
Main Menu
Performing a Site Survey
New Project Wizard
Calibration
Configuration
Data Collection
Understanding Survey Types: Passive, Active, and Predictive
Active Survey Configuration
Best Practices, Tips, and Tricks
Survey Job Splitting
Predictive Surveys
Drawing Walls and Other Obstructions
Drawing Attenuation Zones
Placing and Configuring Virtual APs
Working with Presets
Applying Visualizations
Working with Multi-floor Sites
Mixing Real and Virtual Data
Best Practices, Tips, and Tricks
Analyzing Data – Passive and Predictive Surveys
Selecting Data for Analysis
Adjusting AP Locations After Passive Surveys
Splitting an AP into Multiple Unique APs
Working with Multi-SSID APs
Visualization Types
Signal Level
Signal-to-Noise Ratio
Signal-to-Interference Ratio
AP Coverage Areas
Number of APs
Expected PHY Rate
Frame Format
Channel Bandwidth
Channel Map
Requirements
Analyzing Data – Active Surveys
Selecting Data for Analysis
Visualization Types
Actual PHY Rate
TCP Upstream and Downstream Rate
UDP Upstream and Downstream Rate
UDP Upstream and Downstream Loss
Round-trip Time
Associated AP
Requirements
Spectrum Analysis
Hardware Requirements
Spectrum Data Graphs
Performing Spectrum Analysis Surveys
Viewing Collected Spectrum Data
Exporting Spectrum Data
Reporting and Printing
Customizing Reports
Google Earth Integration
Configuring TamoGraph
Plans and Surveys
Properties
Plan / Map
Environment
Client Capabilities
Requirements
Scanner
Options
Colors and Value Ranges
AP Detection and Placement
Visualization Settings
Miscellaneous
Configuring GPS Receiver
Using GPS Configuration Dialog
Finding the GPS Receiver Port Number
Taking Photographs
Voice Control
Using TamoGraph in a Virtual Machine
Frequently Asked Questions
Sales and Support

Channel Bandwidth

This visualization shows what type of channel bandwidth (also called channel width) is being used in the given WLAN area. Wi-Fi networks use three types of channel bandwidth:

· 20 MHz Legacy: This is a legacy type used by 802.11 a/b/g equipment. Each channel occupies 20 MHz of radio spectrum.
· 20 MHz HT and 40 MHz HT: These are bandwidth types introduced in the 802.11n standard. They occupy either 20 MHz or 40 MHz of spectrum space and use HT-mixed and HT-Greenfield frame formats.
· 20 MHz VHT, 40 MHz VHT, 80 MHz VHT, and 160 MHz VHT: These are new types introduced in the 802.11ac standard. They use 20, 40, 80, or 160 MHz-wide channels. VHT is used only in the 5 GHz band.

Channel bandwidth is shown for the AP that has the strongest signal in the given map area among the APs selected for analysis. This mimics the roaming behavior of client adapters that connected to the strongest AP. While other audible APs may offer other types of bandwidth, a typical adapter will connect to the AP with the strongest signal. You can deselect one or several of the selected APs to see channel bandwidth types for less strong APs.

Double-clicking on the Channel Bandwidth legend on the status bar allows you to configure the color scheme and change its value range.

Suggested Solutions

If you see 20 MHz Legacy or 20 MHz HT channel bandwidth in the areas where you expect to see 40 MHz HT, the following solutions are suggested:

· Check your AP configuration. If you are using newer 802.11n equipment, make sure that it is configured to use 40 MHz or automatic 20/40 MHz channel width.
· Your AP's ability to use 40 MHz channels depends on the wireless environment. A 40 MHz-enabled AP may fall back to 20 MHz mode in some situations (e.g., when an 802.11n client that does not support 40 MHz bandwidth is connected). Because of the changing environment, the site survey results regarding the channel bandwidth may change from time to time. Perform site surveys regularly.
· If you are using legacy 802.11 a/b/g equipment, consider upgrading to 802.11n or 802.11ac.

If you see the HT channel bandwidth in the areas where you expect to see VHT, make sure that your AP is configured to use the 802.11ac mode and that you have correctly configured its channel width. Also, keep in mind that VHT is available only in the 5 GHz band.