While Wi-Fi is undoubtedly of great benefit, one of its major downsides is interference. All sorts of other devices use the 2.4GHz spectrum used by Wi-Fi – microwaves, cordless phones, wireless TV links, video senders, car alarms and even baby monitors! There’s also the problem of neighbouring Wi-Fi networks, particularly if you live in a densely populated area or an apartment.
Wi-Fi comes in three flavours which use the 2.4Ghz radio frequency band – 802.11b, 802.11g and 802.11n, this last one being the latest and fastest. Within this band, 13 channels are available (in the UK and Europe) to choose from although in reality only channels 1, 5, 9 and 13 will ensure no overlapping with a nearby network. To ensure good frequency separation from neighbouring networks make sure to scan for wireless networks before you install your own – and regularly afterward. Most routers in the UK tend to be shipped with their wireless channel set to 1, 6 or 11 as these are the three non-overlapping channels in the US with many set to Ch1 – chances are most of your local networks will be using that channel so not using channel one should get you off to a flying start!
Of course, if you are surrounded by many other Wi-Fi networks the job becomes increasingly difficult. Their interference, along with that of all the other devices mentioned above, is virtually undetectable without using a spectrum analyser like the Wi-Spy.
The placement of wireless devices in relation to walls and ceilings also has an impact on their performance of course, so you need good placement as well as low interference.
If you’re a home user, the entry-level Wi-Spy 2.4i which comes with Chanalyzer Lite Edition should be adequate for your needs. The Wi-Spy 2.4x with the full version of Chanalyzer 3 is aimed at IT consultants and other professionals who need the extra detail. The Wi-Spy DBx is designed for the enterprise environment where IT managers may look after multiple 802.11a networks along with 802.11b/g/n networks.