Wireless Hacks

Antenna Guide

How do you know which antenna is the best for the job? This guide will explain.

The single most effective way to extend the range of your access point or client radio is to add an external antenna. Contrary to popular belief, antennas do not give you more signal than you started with (that’s what amplifiers are for). They focus the available signal in a particular direction, much like what happens when you turn the focus head of a flashlight. It doesn’t make the bulb any brighter, it just focuses what you have into a tighter space. Focusing a flashlight gives you a brighter beam that covers a smaller total area, and likewise, more directional antennas give you a stronger perceived signal in a smaller area. All antennas are somewhat directional, and the measure of their directionality is referred to as gain . Typically, the higher the gain, the better the range (in the direction that the antenna radiates best in).

Another important characteristic of antennas is the phenomenon of polarization [Hack #84].

There are a few general types of antennas suitable for use at microwave frequencies. Each works well for its own application, and no single antenna works best for every application. When actually shopping for antennas, be sure to look at the actual radiation pattern of your antenna to be sure that it fits your needs.

Plan your goals ahead of time, and configure your network to meet those goals. The following sections describe the most common types of antennas, listed ...