Robert from Charleston, North Carolina, called asking how to extend a
network's coverage.

The typical WiFi card or access point offers a 2.2dBI antenna. That's
power to reach about 150 feet. To go farther you'll need to increase
gain. There are two ways to do that.

+ Add an amplifier.

+ Add a high-gain antenna.

The problem with using an amplifier is that it will increase the output
of your WiFi access point, but not improve its reception. In other
it only improves reception one-way. Fortunately, adding a passive
is cheaper and more effective.

Unfortunately, adding an external antenna to your WiFi router is still
black art. Each WiFi access point (WAP) manufacturer uses a different
connector -- for those WAPs that have external connectors, that is. To
an external antenna you'll first need to make sure your WAP has an
connector, then you'll need to find the right "pigtail" for that
Seattle Wireless has an excellent pigtail guide.

Once you have the right pigtail for your WAP, you'll need a cable to
to your antenna. Buy a low-impedance cable designed for this purpose. I
recommend LMR 400 for anything over a few feet. The impedance of normal
coaxial cable is too high for these low power WiFi signals.

Then you'll have to choose an antenna. WiFi antennas come in
and omnidirectional flavors. Directional antennas can increase the
much farther, but only in one direction.

NetNimble Wireless Products offers excellent cable and antenna choices.
For indoor use, its 5.5dBi Omnidirectional antenna is $49 and comes
connectors for the most popular WAPs. For a little more, you can buy
10dBi directional panel to nearly double your range in a single
Using an antenna on both ends (the WAP and computer) can increase range
even more.

Coincidentally, I did this very upgrade as part of our Digital Digs
on The Screen Savers last month. My Apple Airport WAP works pretty well
inside the house, but there's no signal at all to the rest of the
I wanted to get a signal to my barn about 200 feet away and to a little
nearby shade tree where I like to lie in a hammock. Using roof-mounted
or omnidirectional antennas from Buffalo Technology
I was easily able to extend my WiFi to every part of the farm.

One thing to keep in mind, however, is that when you're broadcasting
WiFi to a greater area, it's easier for people to steal your signal.
sure you turn on WAP encryption and password protection to deter
from sneaking into your system.

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