Wireless Hacks

Chapter 5. Do-It-Yourself Antennas

Hacks #70-79

The price of wireless networking hardware has fallen dramatically in a very short time. Wireless adapters now come standard with many computers, and access points are commonplace. Even the price of antennas and related components has fallen sharply as high demand and extreme competition have driven the industry to an increasingly high-volume, low-margin business.

But this hasn’t stopped people from experimenting with finding out just how little it takes to build a working network. There is something almost magical about radio networking. Tales of war driving (and even war walking) aside, just imagine that today in many cities around the world, dozens of invisible networks exist on any given street corner. As you sit at a cafe eating your lunch, you may be completely unaware of the dozens of people simultaneously using the environment around you to communicate with people around the world. I believe that it is largely this mysterious, intangible aspect of unseen global communications that draws people to embark on their own antenna projects. The deeply rewarding feeling of making something useful out of virtually nothing is worth much more than saving a few dollars on a network component.

When comparing antenna designs, there are a number of important factors to keep in mind. The first antenna property that people usually refer to is gain . The gain of an antenna is a measurement of how well it radiates in the direction you intend it ...