Hack66.Extend the Range of Your Wireless Network

Hack 66. Extend the Range of Your Wireless Network

The efficiency and throughput of WiFi networks can vary dramatically. Make sure you get maximum throughput from your wireless network.

If you have more than one PC at home, the best way to hook them together and share a high-speed Internet connection is via a wireless networkin particular, one based on the WiFi standard, which is actually a family of standards known under the umbrella term of 802.11x.

The biggest problem in setting up a home network usually involves running the wires between PCs and a residential gateway. If your PCs are on different floors of your house, you might have to drill holes in your walls, ceiling, and floors and run wire through them. Even when PCs are on the same floor, you have to deal with the problem of wires snaking along the floor.

That's the problem I've had in my 150-year-old home in Cambridge. Drill through a wall, ceiling, or floor here, and you never know what you'll find (horsehair insulation was only one of our many surprises). Even my electrician shudders when he has to take out the drill.

So, for me, a wireless network was a no-brainer. I now have a half dozen PCs and laptops and four printers situated in various parts of the house, all connected via a combination wired/wireless network and sharing a single broadband Internet connection. And when the weather is nice here (twice a year, by my last calculation), I take my laptop out on my back porch and work from there while still connected to the Internet and other PCs and printers in the house.

But there's a catch with all wireless networks, including mine. Wireless networks rarely deliver data at their rated bandwidth speed. One factor affecting bandwidth speed is the distance between the access point and the wirelessly equipped PC. Compaq, for example, notes that at a distance of 150 feet the throughput of its wireless access point drops from 11Mbps to 5.5Mbps, and at a distance of 300 feet it drops to 2Mbps. Even that significantly understates the drop-off in speed, and most people find that the drop-off is much more dramatic than that, most commonly by a factor of two.

WiFi and Buying New Equipment

There are several versions of the 802.11x WiFi standard, so before you buy WiFi gear, you should know what you're paying for because some are much faster than others. The 802.11b standard was the first one to be ratified, and equipment that adheres to it is the least expensive. (This is the standard commonly used by public wireless hot spots in coffee shops, airports, hotels, and other locations.) It operates in the 2.4GHz part of the spectrum and its maximum throughput is 11Mbps.

The newer standard, 802.11g, operates in the same part of the spectrum and has a maximum throughput of 54Mbps, significantly faster than 802.11b. You won't pay much extra for 802.11g gear compared to 802.11b, so if you're buying all your equipment from scratch, it's the best bet.

802.11b and 802.11g equipment work with each other, although with one "gotcha" you need to watch out for. If you mix and match 802.11g and 802.11b equipment, the entire network will operate at the lower 802.11b speed. So, if you have an 802.11g router and 802.11b adapters, the network will run at the slower speed. In fact, if you have an 802.11g router, three 802.11g adapters, and one 802.11b adapter, the entire network will still run at the lower speed, even between the 802.11g adapters and the 802.11g router. The upshot: if you're going with 802.11g, make sure every piece of your equipment is 802.11g, not 802.11b.

You also might come across 802.11g routers and adapters that promise speeds far greater than 802.11g, commonly at 108Mbps. That works only when you buy all the hardware from the same manufacturer because they use proprietary protocols to reach those speeds. If you mix and match components from different manufacturers, you'll get normal 802.11g speeds, not the faster ones.

Distance is only one factor affecting performance. Interference from other devices and the exact layout of the house or office can also affect it dramatically. However, there are things you can do to extend the range of your network and get more throughput throughout your home:

• Centrally locate your wireless access point

This way, it's most likely that all your wirelessly equipped PCs will get reasonable throughput. If you put your wireless access point in one corner of the house, nearby PCs might get high throughput, but throughput for others might drop significantly.

• Orient your access point's antennas vertically

As a general rule, transmission will be better when antennas are vertical rather than horizontal. Keep in mind, though, that this is only a starting point for positioning the antenna. The exact layout of your house might alter the best positioning of the antenna.

• Point the antennas of your wireless PCs toward the access point

Although 802.11 technology does not require a direct line of sight, pointing antennas in this way tends to increase signal strength. USB wireless cards generally have small antennas that can be positioned, but frequently wireless PC cards don't, so you might have trouble figuring out the antenna orientation in a wireless PC card. If you have a wireless PC card that doesn't have what appears to be an antenna, the antenna is generally located at the periphery of the card itself, so point that at the access point.

• Don't place your access point next to an outside wall

If you do that, you'll be broadcasting signals to the outside, not the inside, of the house. That's nice if you want to give your neighbors access to your network, but not great if you want to reach all the PCs in your house.

• Avoid putting your access point or PCs near microwave ovens or cordless phones

Many microwave ovens and cordless phones operate in the same 2.4GHz part of the spectrum as 802.11b WiFi equipment does. So, microwave ovens and cordless phones can cause significant interference. Cordless phones tend to be the bigger problem.

• Avoid placing the antennas of access points or PCs near filing cabinets and other large metal objects

They can cause significant interference and dramatically reduce throughput.

• Consider using external and booster antennas

Some PC cards, notably Orinoco cards, will accept external antennas that you can buy or build on your own. They have a small connector to which you attach a pigtail and wire and then attach that wire to an antenna. (For information about building your own antenna, see [Hack #65] .) Some access points often accept booster antennas that you can buy as well.

If you have a Linksys wireless network and are looking to improve its signal strength, you can buy a number of different add-ons that promise to extend its range and strengthen its signal. The WRE54G Wireless-G range expander, for example, is able to take a WiFi signal and bounce it further along, expanding your network's range. It works with both 802.11g and 802.11b routers. And Linksys High Gain Antennas will strengthen your network's signal. Unscrew the antennas from your existing Linksys router, and screw these new ones into place. It also works with 802.11b and 802.11g routers.

Other manufacturers sell similar products, so check your router manufacturer's web site for details.

• Try and try again

The ultimate way to find the best placement for your access point and wireless PCs is to continuously experiment and see what kind of throughput you get. Each house and office is so different that no single configuration can suit them all.

Carefully monitor your throughput as you make these changes so that you determine the best positioning for your access point and PCs. To determine your true throughput, use the free network analysis program Qcheck [Hack #67] .

7.3.1. See Also

• [Hack #67]

• [Hack #65]