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Wi-Fi analysis tools

By , Network World
April 02, 2008 04:55 PM ET

Network World - First up this week, a terrific Wi-Fi hot-spot finder, the HS20 Digital Hotspotter from Canary Wireless. This is a small rectangular box (3.19 inches long by 2.13 inches wide by 0.65 inch high and only 2.5 ounces) that can detect 802.11 b, g or n networks and is immune to Bluetooth, cordless phones or other interference in the Wi-Fi band.

The Canary Hotspotter has a backlight (critical if you are, say, stuck in an air conditioning duct) and enumerates the information about each Wi-Fi network it finds, showing open and secure Wi-Fi devices along with their signal strength, network ID (SSID), encryption method (none, WEP, WPA or WPA2), and channel used.

Retailing for $60, this is the hottest hot-spot detector I’ve seen so far.

Now, while finding Wi-Fi hot spots can be crucial to road warriors, the techs back at the mothership have completely different Wi-Fi concerns. For these chaps the challenge is to craft a Wi-Fi infrastructure that works and does so as well as possible.

A few Internet decades ago (January this year) I reviewed a USB spectrum analyzer manufactured and sold by MetaGeek called the Wi-Spy 2.4x.

This cool device ($400 with software) scans the radio frequency range from 2400 MHz to 2483.5 MHz – the range of Wi-Fi (natch) -- and, using MetaGeek’s Chanalyzer software, analyzes and displays the characteristics of this spectrum segment. Since my review, MetaGeek has released a new version of the software (Version 3.0),  and what a great upgrade!

MetaGeek appears to have improved the sensitivity of the analysis – the Topographic View (amplitude plotted against frequency) appears much quicker – and it has also spiffed up the user interface, most notably adding a sidebar. This sidebar has tabs for recording and sharing trace data, taking notes, sending feedback to MetaGeek, and inspecting the details of any point on any of the three analysis views.

There’s one more tab in the sidebar and this is the biggest enhancement: Profiles. This tab shows thumbnails of the activity of specific devices as shown in the Topographic View. By clicking on a thumbnail, the cursor is replaced by a curve that is characteristic of the selected device so you can overlay it on the current Topographic View. That helps you identify the sources of interference that you find in your environment.

While Wi-Spy and Chanalyzer are great tools for sorting out spot problems, for any installation with more than a handful of Wi-Fi access points, you’re going to want to profile your entire building or campus so you know where to start looking for problems. You’re going to need VisiWave, published by AZO Technologies (the software-only versions for Windows laptops or Pocket PC handheld computers costs $549).

VisiWave uses your laptop’s Wi-Fi adapter (the company has a list of supported adapters to collect signal strength and identity data from Wi-Fi devices -- access points and ad hoc networks). Even better, VisiWave can work with Wi-Spy to collect interference data.

You can buy VisiWave with AZO’s navigation unit, a high-tech dead-reckoning system that can be used indoors where GPS doesn’t work, to automatically capture position information (the software and hardware bundle is rather more pricey, at $2,495). If you are working on a larger scale, ViziWave can also use GPS data for location data.

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