Give Your Wireless Signal a Boost

By Ronald Pacchiano | Posted September 24, 2004

More on Networking

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 with Internet access through a Comcast cable modem. My other two computers are both equipped with D-Link DWL-650 wireless network adapters. The first one — a Dell Dimension desktop PC — resides about 25 feet away from my primary computer, and I use it to access the Internet and shared files. According to the D-Link configuration utility, the wireless link quality and signal strength varies from 33 percent to 85 percent.

The problem I'm experiencing has to do with my third computer. This is a Toshiba laptop, and it's 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 may vary from a high of 55 percent, all the way down to nothing.

When I use the laptop downstairs, the signal strength increases to about 60 percent — in spite of 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 the closer I get to the deck. I can't understand how a distance of barely 30 feet could cause such a dramatic change in the signal quality.


What has caused the wireless signal strength to degrade so dramatically since I installed the network, 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 was 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?

There are a number of variables that could cause your wireless network signal quality to fluctuate so dramatically. For starters, you might have a problem with range. Typically, the operating range of an indoor wireless network at 11Mbps would be well over a 100 feet — greater than that in an open area like a hall or auditorium.

However, this range can significantly decrease depending on the environment you're in. Most homes constructed of wood and sheetrock aren't too restricting, but a building made of steel and concrete can cause considerable interference. Other things, like cordless phones and microwaves can also hinder performance. So whereas I might be able to get over 150 feet from my wireless router, you might be able to go only 75 feet from your wireless router.

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 restricting the range and reliability of your wireless network. So even though you're traveling only 80 feet from the router, you can still be out of the router's operational range.

Here are several options. 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 you can put them in any room with a phone line or cable connection.

Additionally, placing the router in a higher location could also help compensate for a weaker signal. Using D-Link's diagnostic utility you could also monitor your signal strength when the phone or microwave is in use to check for any fluctuations in link quality.

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, the signal strength begins to degrade. The farther the signal travels, the weaker it becomes — until finally it loses its integrity. This is known as attenuation.

A repeater picks up the weak signal, regenerates it and then rebroadcasts it, thus extending the range of your network. This regeneration makes the signal stronger, making it possible to overcome some of the interference you might be encountering.

After you configure the repeater to work with your network, simply plug it in somewhere between the router and your deck. This should extend the range of your wireless network to cover the balcony. Placing it on top of a wall unit might even help compensate for the fluctuating signal on the Dell machine upstairs, as well. You can confirm the performance improvement use 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 DWL-800AP+. It's an enhanced 802.11b wireless range extender that can operate as a wireless access point or wireless repeater. The unit has a street price of about $65, so it's very affordable. Best of luck!

I don't have a very extensive computer background, but I would like to add a wireless router to my home office network. While researching for a router I keep coming across the term NAT. It seems to be important because all of the routers I've looked at list it as a feature, but I don't know what it is or what it does. Could you explain it to me? Thanks!

No problem. NAT is an abbreviation for Network Address Translation. To put it simply, NAT is an Internet standard that lets a local-area network (LAN) use one set of (Private) IP addresses for internal traffic and a second set of (Global) IP addresses for external traffic. The NAT device resides at the point where the LAN meets the Internet.

A NAT inside the router translates any incoming data on that Global address to the destination of the private IP address of the PC that requested it. When it's time to send that data back, the NAT strips away the private IP address information and replaces it with the Global IP address of its destination.

NAT has two primary purposes. First, it provides a type of security for your network by hiding all of your PCs behind a single IP address. Since only the NAT device knows what Internet traffic is going to what PC on the local network, it forces all data packets to be examined before granting them access to the internal network. This helps to protect your PC from unauthorized access by an outside threat; like a hacker or a Denial of Service (DoS) attack.

Secondly, NAT reduces the need for a large amount of publicly known IP addresses by creating a separation between publicly known and privately known IP addresses. This lets a company use more internal IP addresses. S ince they're used internally only, there's no possibility of conflict with IP addresses used by other companies and organizations. Not to mention that it also helps to reduce the IP address depletion problem because all of a company's communications can be routed through just a handful or as few as one Global IP address.

NAT capability can be found in every router on the market today.

Adapted from PracticallyNetworked.com, part of the EarthWeb.com Network.

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