Chanalyzer: how to work out what’s wrong with your Wi-Fi

I found out about the excellent Chanalyzer Pro software from my Real World colleague Paul Ockenden several months ago. It’s a superb piece of Wi-Fi diagnostics software, and now there’s a new version, which adds considerably to the functionality.

The software doesn’t really do much by itself; you need a USB dongle, too. It’s available in various versions, depending on how much functionality you require. I needed coverage for both the 2.4GHz Wi-Fi range and the 5GHz N range, so I bought the software with the Wi-Spy DBx unit.

If you’re a sysadmin and have to support a Wi-Fi network in your office, frankly you need this tool

This USB dongle is actually a tiny radio frequency spectrum analyser. It does much more than just look for Wi-Fi signals, because the 2.4GHz frequency space is used by all sorts of things other than just pure Wi-Fi. If you’re having problems with interference or poor throughput, it might be down to a device using the same frequency space. You won’t see it on your list of Wi-Fi devices since it isn’t a Wi-Fi device.

The software gives you a fantastic view of what’s happening in the 2.4GHz space. I installed everything on a Dell laptop, so I could carry the whole analysis toolkit around with me.

On the left-hand side, a rolling view of time shows if there are transmitters that are always on, such as a video camera that’s transmitting constantly. You’d see this as a vertical line running along the time axis. Then there’s a big window that shows the Wi-Fi channel numbers from 1-13. The software builds up an analysis of what’s going on, and then overlays all the Wi-Fi base stations on the diagram.

This is hugely useful for determining if your base station is trying to sit on top of something that your neighbour is running too. You can then identify clear channels that might be available to your base.

Finally, you get an analysis of the Wi-Fi namespace of bases. The software uses the laptop’s built-in Wi-Fi connection for this and presents you with a list of base names, signal strength sparklines, product names, information about privacy and security settings, the MAC address of the device, its supported transmissions rates and so forth.

The amount of information you get is stunning.

It paid for itself on its first “professional” outing, where I was trying to sort out the Wi-Fi in a client’s office. By firing up Chanalyzer and letting it collect a few minutes of data, I was immediately able to see how the Wi-Fi networking was badly set up and where there was some relatively quiet space. After some configuration of the base stations, everyone was stunned at the improved throughput and reliability of the office wireless LAN.

Of course, you can’t stop other people moving their bases around. So having this tool trundling along in the background is useful if you want an instant explanation when problems arise. If you’re a sysadmin and have to support a Wi-Fi network in your office, frankly you need this tool. The normal management tools for Wi-Fi are usually grossly inadequate. We all have to live in a shared Wi-Fi space, and Chanalyzer not only provides a good service to your users but also helps you to minimise the impact on your neighbours.