Increasing The Range Of Your Wireless Access Points
By Lee Asher, Wed Dec 7th
How far can wireless go? Well, really, the answer is as far asyou want it to, or as far as you can afford. You see, eventhough each wireless transmitter has a range limit, you caninstall things called wireless extension points, often calledrepeaters, to boost the signal and make your network's rangeeven longer.
So you're not getting the 11Mbps speed that you thought yourcard's manufacturer promised? If you read your card or AccessPoint's spec carefully, you'll probably see that data rates arespecified as a function of distance. Data rate drops off veryquickly with distance for 802.11b products.
What is a Repeater?
As you get further away from the origin of a wireless signal, itgets weaker and weaker, until eventually it is impossible toreceive at all. No matter how much you spend on high-poweredwireless equipment, you will eventually reach a point where yournetwork just won't stretch any further.
Some people solve this problem by running wires out as far asthey want the network to go, and having it 'break out' intowireless every so often using a wireless access point. This canbe more trouble than it's worth, though -- what's the point ofinstalling massive lengths of wire just to cover an area withwireless access? You could just put ports in the wall, couldn'tyou?
Well, to fix this dilemma, some manufacturers have started toproduce wireless repeaters, even though they're not part of thewireless standard. These 'extension points' work as a relay,simply taking the existing wireless signal and making itstronger, making the range of the signal larger each time.
If you place the repeaters correctly, this can make it so thatyou can move computers a long way away from the wired part ofthe network (the router or access point) without stopping themfrom working. The only requirement is that the ranges of thepoints must overlap -- after all, a repeater can't repeat asignal that it can't receive.
How Do They Work?
To understand how repeaters work, you must remember thatwireless
networking signals are really just radio signals.Repeaters simply take all the radio signals they receive on thefrequency used by wireless communications (2.4Ghz) and use theirpower to amplify and re-broadcast them. This process does notdegrade the signal, and can be done as many times as necessary.
In theory, you place wireless repeaters in a line for severalmiles and so extend a wireless network out that far. Becauseextension points don't need all the computer technology requiredin 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 anddirectional antennas (antennas that focus a wireless signal inone direction) to connect two LANs that are miles apart. Theyfind it's cheaper to do things this way than to worry about theproblems that come with doing it over the Internet or to installtheir own underground wires. It is technology like repeatersthat could, in the future, help to build wireless networkscovering whole towns and cities.
Choosing a Repeater
For the moment, you're limited to the bigger manufacturers whenchoosing a repeater, and even some of them have it missing fromtheir product range. Different companies give their repeatersdifferent names, such as 'Range Expander' (Linksys) or 'RangeExtender' (D-Link).
When you're thinking of buying a wireless extension point, thereare some things you need to think about. The most importantthing is whether it will work with your existing equipment --because there's no formal standard for wireless extensionpoints, there's no guarantee that one you get will work on yournetwork. It's best to stick to the same manufacturer that youhave the rest of your equipment from, or at least do a websearch to find other people who've made the combination work.
Another consideration is whether the extension point has anyEthernet ports. It's not an essential feature, but it can beuseful if you want to connect the extension to a wired network.This is mainly only important if you're trying to connect twoLANs wirelessly, although Ethernet can also be useful forconnecting devices if something breaks and you need totroubleshoot the network.