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Troubleshooting Q&A - November 13, 2003 Wireless Networking Performance Tips Suffering from wildly fluctuating wireless connection speeds or having trouble getting any connection at all? This week's Q&A offers some tips and tricks for helping you get the maximum speed out of your wireless network. By Ron Pacchiano Q. In my home I have three PCs. My primary system is a Compaq EVO running Windows 2000. It’s connected to a Linksys EtherFast AP Cable DSL Wireless Router, and Internet access is being provided via a Comcast cable modem. My other two computers are both equipped with D-Link DWL-650 wireless network adapters. The first is a Dell Dimension desktop that resides about 25 feet away from my primary computer and is typically used to access the internet and some shared files. According to the D-Link configuration utility, the wireless link quality and signal strength varies from 33% to 85%. The problem I’m experiencing has to do with my third computer, a Toshiba laptop located one floor above my primary computer. For the last few weeks this system has been having an increasingly difficult time maintaining its link to the wireless router. The link quality and signal strength for this machine has varied from a high of 55% all the way down to nothing (0%). When I use the laptop downstairs, the signal strength increases to about 60%, despite the fact that it’s separated from the wireless router by about 30 feet and one wall. I’d like to be able to use the laptop on my deck, which is about 50 feet away. Unfortunately, the signal strength decreases to practically nothing as I get closer to the deck. I can’t understand how a distance of barely 30 feet could cause such a dramatic change in the signal quality. So my questions are what could have caused my signal strength to degrade so dramatically since the network was installed, and what can I do to improve the link quality, or at least maintain my link, while I’m working on my laptop? I checked D-Link’s site for a new driver or firmware update, but I am already running the latest ones. I really would like to be able to use the wireless network from anywhere in my home without worrying about losing my high speed internet connection. Do you have any suggestions? A. There are a number of variables that could be causing your wireless network’s signal quality to fluctuate so dramatically. For starters, you might be experiencing a problem with range. The typical operating range of an indoor wireless network at 11Mbps would be well over a 100ft, and greater than that in an open area like a hall or auditorium. However, this range can be significantly decreased depending on the environment you’re in. Most homes are constructed of wood and sheet rock, materials they aren’t overly restrictive in terms of affecting wireless signals, but a building made of steel and concrete can cause considerable interference. Other devices such as cordless phones and microwaves can also hinder performance. So whereas I might be able to get over 150ft from my wireless router, you might only be able to go 75ft from yours. The fact that your transmission rate has a tendency to drop so significantly from time to time leads me to believe that something is causing interference and is consequently restricting the range and reliability of your wireless network. So even though you’re only looking to travel about 80 feet from the router, you can still be out of the router's operational range if something interferes with — and as a result, degrades — the quality of your wireless connection. There are some things you could try that might possibly help you get around this problem. You might want to consider relocating the router to another part of the room or moving it to another floor altogether. One benefit of cable modems and DSL lines is that they give you a good deal of flexibility on were they can be located. In general, any room with a phone line or cable connection can be used. Additionally, placing the router in a higher location could also help compensate for a weaker signal. You could also monitor your signal strength using D-Link’s diagnostic utility when the phone or microwave is in use to see if any fluctuations in link quality occur. Best Advice: Invest in a Repeater Honestly, though, I think the best way for you to get around this would be to simply purchase and install a repeater. You see, when you first broadcast a wireless signal, it is very strong. As it continues to travel away from its source, though, the signal strength begins to grow weaker. The farther the signal travels, the weaker it becomes, until finally it completely loses its integrity. This process is referred to as attenuation (definition). A repeater picks up the weakened signal, regenerates it, and then rebroadcast it, thus extending the range of your network. This regeneration also makes the signal stronger, making it possible to overcome some of the interference you may be encountering. After the repeater has been configured to work with your network, simply plug it in somewhere between the router and one of the wireless PCs. The repeater should easily extend the range of your wireless network to cover the outside deck. If you place it on top of a wall unit, it might even help compensate for the fluctuating signal on the Dell machine upstairs as well. You can confirm the performance improvement using D-Link’s wireless monitoring utility to measure the signal strength both before and after the installation. My personal recommendation for a wireless repeater is the D-Link AirPlus 900AP+. The D-Link AirPlus 900AP+ is officially listed as an access point, but it is user-configurable to perform different tasks, such as serving as a wireless bridge, a wireless client, or, of course, a repeater. The unit has a street price of about $65, making it very affordable. I actually wrote a full review of the unit awhile back. It can be found online at http://www.80211-planet.com/reviews/AP/article.php/1492131. Alternatively, Linksys and Netgear also have good products available that should meet your needs. If for some strange reason the repeater doesn’t improve your performance, you might want to consider another wireless alternative. You might consider looking into a Powerline-based bridge. These devices use your home’s AC wiring as a conduit to network computers, but they can also be used to connect two or more networks within your home. For example, connecting an Ethernet-to-Powerline bridge to your router, and then a Powerline-to-wireless bridge to the second network should give you the connectivity between the locations you require. Some of the best Powerline products I’ve seen are the Siemens SpeedStream line. They can be found at http://www.speedstream.com/products_powerline.html. I hope this helps. Good luck!
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