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Hack 49 Adding an Antenna to the AirPort

Significantly extend your range when using an
AirPort base station.

As stated many times in this book, the
single most effective method for extending range is to use a good
antenna. Most access points ship with a simple dipole or small omni
that doesn't offer much gain, but at least gets the
antenna away from the body of the access point. The Apple AirPort is
a somewhat expensive AP that includes an integrated antenna but no
external antenna connector. This state of affairs has been corrected
on their newest AirPort Extreme models, which
include an external antenna
connector, but there are a huge number of older AirPorts deployed
that rely on the internal antenna for communications.

Luckily, the radio inside the Graphite AirPort is a Lucent/Orinoco/Avaya
Silver card, which includes an antenna connector of its own. With a
little bit of work, it is possible add your own external antenna. All
you need is a screwdriver, a dremel tool, a Lucent pigtail [Hack #66], and about half an
hour.

As you can see in Figure 4-5, the only ports on the back of a Graphite
AirPort are the modem, power, and Ethernet. The rest of the AirPort
is sealed, and there isn't room to squeeze a pigtail
in without cutting a hole in the chassis. I found that I used the
modem only once since I bought the AirPort, so rather than cut a hole
in the side of the AirPort, I could just remove the telephone jack
and feed the pigtail through the little square.

There are three Philips head screws on the bottom of the AirPort.
Remove them, and carefully remove the bottom half of the shell. There
is an internal case that is held to the top by three more screws.
Remove them, but don't tilt out the internal case
yet. There is a tiny cable connecting the telephone jack to the
motherboard, covered with a piece of silver metal tape. Pry up the
tape, and carefully disconnect the modem connector. Now you should be
able to carefully tilt out the internal case. This is the motherboard
and radio card of the AirPort, which attaches to the ports by two
short cables (an Ethernet cable and a twisted red and black power
cable). Remove them as well.

If you have never played with a
Lucent/Orinoco/Avaya Silver card before,
there is a tiny black plastic cap covering the antenna connector on
the edge of the card. Pry out this cap and discard it, as shown in
Figure 4-6.

Notice how the radio card fits snugly against a black plastic rail on
the top half of the outer shell. There isn't enough
room to accommodate a pigtail when reassembling the AirPort, so you
need to grind away some of this plastic, or possibly use a good pair
of cutters to nibble it away. A right-angle pigtail works much better
than a straight pigtail, as there isn't much room to
maneuver inside the case.

If you would rather just punch a hole in the side of the AirPort
case, you can do that now as well. I prefer to feed the pigtail
through the modem port, which involves removing the entire port
chassis. There are two screws holding a metal plate to the top half
of the outer shell. Remove them, and the entire port chassis will
pull out of the case. There are two tiny screws holding the telephone
jack to this metal plate. You need a tiny Phillips head screwdriver
to remove these screws. A jeweler's screwdriver (as
you might find in an eyeglass repair kit) works well.

Now reverse the steps, carefully tucking in the cables as you screw
everything back together again. Figure 4-7 shows an
8" pigtail fed through the modem port.

I didn't have one handy, but a better hack would be
to use a chassis mount N or TNC connector to bolt directly to the
modem port. That would be more rugged, and would help avoid the
possibility of accidentally yanking too hard on the pigtail and
damaging the connector or card. Also note that while a pigtail is
connected to a Lucent card, the internal antenna is switched off, so
you will get very terrible coverage unless you connect the pigtail to
an antenna.

This technique can be used for other devices that include an internal
card with antenna connectors, such as the Proxim RG1000 or RG1100.
Many APs now come standard with external antennas, but if you should
encounter one that doesn't, this modification can
improve your range significantly.