Hack 55. Increase the Range of a PowerBook

Radio waves don't penetrate metal well, but that shouldn't keep your PowerBook from getting online.

Apple's PowerBook is arguably one of the most aesthetically pleasing laptops on the market. Its wide-screen display is particularly striking, and like the rest of Apple's entire line, it can accommodate a built-in AirPort card. Unfortunately, while the choice of titanium or aluminum for an outer shell might make the PowerBook pleasing to the eye and touch, it wreaks havoc with wireless.

The all-metal case acts as an effective Faraday cage, blocking radio signals from anywhere but the tiny plastic antenna ports on either side of the keyboard. To make matters worse, the antenna ports coincide with the exact position that most people rest their hands when not typing. When this happens, it's all too common for connectivity to drop altogether as the client radio desperately tries to find a path to the access point (AP).

Apple made a stab at solving the problem with the latest PowerBooks, which have an aluminum skin instead of titanium. The properties of aluminum are such that the interference decreased, but did not go away. Some users report increased coverage simply by making sure that the antenna connector is firmly seated in the AirPort card, as it can sometimes become dislodged slightly after leaving the factory. But even with a perfectly operating card and antenna, PowerBooks routinely see about half of the range of the cheaper plastic iBooks, which have a much more visible internal antenna.

Fortunately, there is hope. Since the PowerBooks have a PCMCIA slot, it is perfectly possible to add another wireless card and use it instead of the builtin AirPort. The biggest drawback to this approach is that Apple's nicely integrated wireless tools work only with the internal AirPort card, so you will have to get used to using other means to control your wireless connection. But the two- to four-fold increase in range can be well worth the effort.

The WirelessDriver project lives on SourceForge at http://wirelessdriver.sourceforge.net. At the time of this writing, it is confirmed to support more than 40 different wireless cards under Mac OS X, and probably supports many more. It works with Prism-based cards as well as Hermes and Aironet cards. The software is available in a disk image installer, so no compilation is needed.

One popular add-on card is the EnGenius/Senao series, particularly the 2511. It puts out 200mW and is a particularly sensitive radio. It comes in two versions, with and without an internal antenna. If you use the 2511-CD+EXT2, you need an external antenna, such as an 8dBi patch [Hack #52], as it has no internal antenna of its own. A good choice for a card with an internal antenna and an antenna connector is the Lucent/Orinoco/Proxim Silver or Gold card. Like the internal AirPort card, it puts out only 30mW, but is fairly sensitive, and quite inexpensive, averaging about $30 at this point.

Remember that the best thing you can do to improve the range of any wireless device is to make its antenna as visible as possible to the access point you are trying to communicate with. While an add-on card might not be as convenient as the built-in AirPort card, anything is better than hiding your antenna behind a suit of armor.

Bluetooth, Mobile Phones, and GPS

Network Discovery and Monitoring

Wireless Security

Hardware Hacks

Software Hacks

Do-It-Yourself Antennas

Wireless Network Design

Appendix A. Wireless Standards

Appendix B. Wireless Hardware Guide

Wireless Hacks
Wireless Hacks: Tips & Tools for Building, Extending, and Securing Your Network
ISBN: 0596101449
EAN: 2147483647
Year: 2004
Pages: 178

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