Taking It Long-Distance: Wireless Extension Points.

How far can wireless go? Well, really, the answer is as far as you want it to, or as far as you can afford. You see, even though each wireless transmitter has a range limit, you can install things called wireless extension points, often called repeaters, to boost the signal and make your network's range even bigger.

What is a Repeater?

As you get further away from the origin of a wireless signal, it gets weaker and weaker, until eventually it is impossible to receive at all. No matter much you spend on high-powered wireless equipment, you will eventually reach a point where your network just won't stretch any further.

Some people solve this problem by running wires out as far as they want the network to go, and having it 'break out' into wireless every so often using a wireless access point. This can be more trouble than it's worth, though -- what's the point of installing massive lengths of wire just to cover an area with wireless access? You could just put ports in the wall, couldn't you?

Well, to fix this dilemma, some manufacturers have started to produce wireless repeaters, even though they're not part of the wireless standard. These 'extension points' work as a relay, simply taking the existing wireless signal and making it stronger, making the range of the signal larger each time.

If you place the repeaters correctly, this can make it so that you can move computers a long way away from the wired part of the network (the router or access point) without stopping them from working. The only requirement is that the ranges of the points must overlap -- after all, a repeater can't repeat a signal that it can't receive.

How Do They Work?

To understand how repeaters work, you must remember that wireless networking signals are really just radio signals. Repeaters simply take all the radio signals they receive on the frequency used by wireless communications (2.4Ghz) and use their power to amplify and re-broadcast them. This process does not degrade the signal, and can be done as many times as necessary.

In theory, you place wireless repeaters in a line for several miles and so extend a wireless network out that far. Because extension points don't need all the computer technology required in a router or an access point, they are relatively inexpensive, and so this possibility isn't as unlikely as it sounds.

Some companies, for example, use a combination of repeaters and directional antennas (antennas that focus a wireless signal in one direction) to connect two LANs that are miles apart. They find it's cheaper to do things this way than to worry about the problems that come with doing it over the Internet or to install their own underground wires. It is technology like repeaters that could, in the future, help to build wireless networks covering whole towns and cities.

Choosing a Repeater.

For the moment, you're limited to the bigger manufacturers when choosing a repeater, and even some of them have it missing from their product range. Different companies give their repeaters different names, such as 'Range Expander' (Linksys) or 'Range Extender' (D-Link).

When you're thinking of buying a wireless extension point, there are some things you need to think about. The most important thing is whether it will work with your existing equipment -- because there's no formal standard for wireless extension points, there's no guarantee that one you get will work on your network. It's best to stick to the same manufacturer that you have the rest of your equipment from, or at least do a web search to find other people who've made the combination work.

Another consideration is whether the extension point has any Ethernet ports. It's not an essential feature, but it can be useful if you want to connect the extension to a wired network. This is mainly only important if you're trying to connect two LANs wirelessly, although Ethernet can also be useful for connecting devices if something breaks and you need to troubleshoot the network.