Wireless networks are great ­ until they go wrong, that is.

For example, you want to connect a new wireless client to your network but can’t remember, or don’t know, the type of encryption or keys required. And then, when you check the settings on the wireless router or access point, you’re asked for a username and password and can’t remember those either.

Of course, you should have changed the default administrator account and password, and made a note of the new settings, but a lot of us don’t ­ in which case you might want to try some of the common defaults.

1 Blankety blank
A username of ‘admin’ and password of ‘admin’ will often get you into a router’s setup page, as can ‘admin’ and either a blank password or the word ‘password’ itself. You might also try a password of ‘1234’, or on some devices a blank username and password of ‘admin’.

If all else fails, you can reset most wireless routers back to their factory defaults, typically by pressing a small reset button at the back or underneath. However, you will then have to reconfigure all its settings from scratch.

2 Up-to-date software
Wireless networking is relatively new and the technology is still evolving. As a result, you can solve a lot of connectivity and other problems simply by downloading and installing the latest firmware or drivers for your wireless devices. Some of the latest security enhancements are only available if you’re running up-to-date software.

The version of Windows involved can also have a big effect. Microsoft didn’t really start getting its wireless act together until Windows XP was launched, which means that if you’re running anything earlier you’re dependent on the software provided by hardware vendors.

Windows Vista has the most up-to-date wireless support, but if using Windows XP it’s worth making sure Service Pack 2 (SP2) is installed as the wireless options were greatly enhanced in this update and it addresses a lot of connectivity and security issues.

3 A matter of range
There are lots of things you can try in order to improve the coverage of your network. First, locate your wireless router or access point as centrally and as high up as possible. You can also upgrade to high-gain antennas, although it’s not always possible, especially on cheaper devices that don’t have antenna sockets, and it’s important to check compatibility before buying.

On a business network, install additional access points to improve coverage, while on a home Lan consider a Powerline range extender such as the WGXB102 from Netgear. This comprises two small wireless devices that plug into standard mains power sockets ­ one connects to the wireless router, the other acts as an access point and needs to be close to the client PCs. The mains wiring then acts as a backbone network joining them together.

Lastly, you might want to look at the latest ‘Draft-N’ products. Designed to conform to the forthcoming 802.11n specification, these offer greater throughput and range. However, you will need to upgrade all your wireless devices to get the full benefit.

4 Interference issues
If you’re having trouble connecting to a wireless Lan or the connection becomes intermittent, interference could be a contributing factor. Wifi shares the 2.4GHz waveband with a lot of other technologies, including wireless TV senders, baby monitors, wireless alarm systems and Bluetooth devices. Microwave ovens can also cause problems. If you have any of these, try turning them off to see if the situation improves.

You may also want to experiment with the wireless channel used by your router/access point, especially if there are any other wireless networks nearby. Although there are 13 channels available for the most popular 802.11g technology in Europe, most routers and access points come configured to use channel 6. Try changing to a different channel number to see if that helps. Channels 1, 6 and 11 are completely separate and should be tried first; all the others overlap a little.