Saturday, 14 November 2009

Wi-Spy 2.4i - A Great Tool for WiFi Problems


I've frequently written about the value of a little piece of freeware called InSSIDer when it comes to checking which wifi channel might be the best for you to use, to avoid conflict with a neighbour's router that might be on the same channel. If you have a wireless router, I really cannot recommend InSSIDer enough for every wireless equipped machine you have.

InSSIDer is produced by a company called metageek who produce a range of spectrum analysers - widgets that can help locate sources of wifi interference. The 'baby' of the range, shown at the top of the page, is the Wi-Spy 2.4i. metageek also produce a range of these devices that operate in the 2.4 GHz (802.11b/g), 5 GHz (802.11a/b/g/n)and 868 and 915 MHz bands.

If you want to see in detail what these devices can do, then it is worth spending a little time exploring the metageek website.

Perhaps the best way of understanding what the Wi-Spy 2.4i can do, is to look at a couple of traces from it. The device can output the 2.4 GHz spectrum in a variety of 2D ways and as a 3D display (but not all 3D-capable video cards are yet supported for the 3D display). To be honest, whilst the 3D display is pretty, I've found the the 2D displays to be more useful so far. The trace above (click on it to get a larger view)shows the 'Waterfall' view and the 'Density' view seen by my PC. The Density view is overlaid by the output from my wireless adapter, so you can see my router (solid green line) sitting on Channel 6 and my neighbour's router (solid red line), which is on Channel 1. The blue speckles surrounding the green line are the output from my router, in this case a 2-Wire 2700 operating in 802.11 b/g mode.

Now, lets take a look at some interference. In the trace above (again, click to see an enlargement), I've managed to identify some of the things that might cause my WiFi connection problems - and there are a couple of things that are still a bit of a mystery. I've also switched off the wireless adapter output, so that the W-Spy 2.4i output is a little clearer.

In the upper Waterfall display, I've labelled some of the sources of radio frequency emissions. Most obvious is the green vertical bar close to Channel 9. It turns out that this is the car alarm in my Toyota Previa. There are similar bars near to channel 6 and channel 13 that may also be car alarms, but I haven't yet shown that for certain.

A little harder to see are the array of green and yellow speckles that form a horizontal line across Channels 9 to 13 at the bottom of the Waterfall display. This it turns out, is characteristic of my microwave oven. So, although Channel 11 (one of the three non-overlapping channels in the UK) is free from wifi routers, it's probably not going to be a good channel to use as it will be affected by both the microwave oven and the car alarm.

There is an odd source of interference that appears best in the Density trace below and is labelled #2. It's not clear, yet, what is causing this. It's not my PC, nor any of the ancillary equipment. I've also eliminated my DECT phone, Homeplugs, Skybox, TV and a host of other things. Because of the way the trace was obtained and the close proximity of the router, it is possible that the router itself is being picked up by the Wi-Spy. Clearly, I've a bit more work to do on this.

In a nutshell, that's what the Wi-Spy 2.4i does - helps you find and eliminate, or avoid, sources of interference.

If you are in the UK, you can find Wi-Spy at Crownhill Associates for £68.94 (inc VAT). OK, it isn't cheap, but if you are having wifi problems, it could save you a lot of time and effort - and money spent on other solutions that don't work.

The other bit of good news is that Wi-Spy 2.4i works with both PCs (XP and Vista) and Macs (OSX 10.5).

As for me, I've been so impressed after only a few day's use, that I'm going to have to save up for the WiSpy 2.4i's big brother!

UPDATE: You can see a recent success with the Wi-Spy here. It shows what you might expect if you are hit with repetitive electrical impulse noise (REIN)

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Having had some major problems with my own broadband service, I understand how others struggle to get help from BT.

There is a lot of good information out there, but it can be hard to find. So this blog is an attempt to pull some of it together, in one place.

It's a blog that really shouldn't be needed - if only BT and possibly other ISP's in the UK, provided useful customer support.