Hack 55 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
network—in 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 the house, you may have to drill holes in
your walls, ceiling, and floors and run wire through. 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 got
half-a-dozen PCs and laptops and three printers in remote parts of
the house from each other, 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 11
Mbps to 5.5 Mbps, and at a distance of 300 feet it drops to 2 Mbps.
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.
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There are several versions of the 802.11x WiFi
standard, and unfortunately, they don't all work
with one another. So, when you're buying WiFi
equipment such as hubs/routers, make sure they're
compatible. The 802.11b standard was the first one to be ratified, is
the most common type of WiFi network, and its equipment 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 2.4 GHz
part of the spectrum and its maximum throughput is 11 Mbps.
Increasingly popular, though, is the
802.11g standard, which also operates in the 2.4 GHz part of the
spectrum but has a much higher maximum throughput: 54 Mpbs. 802.11b
cards will connect to a 802.11g access point, but only at a maximum
of 11 Mpbs. However, 802.11g cards can't connect to
an 802.11b access point. As of this writing, problems have been
reported using 802.11b hardware on an 802.11g network, however. There
have been reports of incompatibilities and of the 802.11b hardware
slowing the entire 802.11g network down to its slower speed. However,
that's because the 802.11g hardware was built when
the standard was only a draft and not a final standard. The standard
has since been finalized, so if you buy new equipment, you should be
safe. Be wary of buying older, used equipment, though.
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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 of your wirelessly equipped PCs will get reasonable
throughput. If you put it in one corner of the house, nearby PCs may
get high throughput, but throughput for others may 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 its
antenna. The exact layout of your house may 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 them 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 may 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 2.4
GHz part of the spectrum as 802.11b WiFi equipment. 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
both 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 #42]). 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 $99 add-in that
promises to extend its range and strengthen its signal. The WSB24
Wireless Signal Booster sits on top of your existing wireless router.
You take the antennas off your router, attach them to the booster,
then attach the booster to the router via cables. I
haven't tried it myself, so I can't
personally vouch for it, but those who have tried claim it works.
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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 #57].
5.15.1 See Also
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