As I mentioned earlier in this chapter, if you want to buy an antenna cheaply, you may have good luck on eBay. I recently tried the terms "RF antenna" and "Wi-Fi antenna" on eBay, and found quite a few items for auction, with almost none priced above $25.
If you decide to buy your antenna in a more conventional way, you should go to a company with a Web presence that specializes in RF antennas and related equipment. These companies include
CushCraft Corporation: www.cushcraft.com
Fleeman, Anderson & Bird: www.fab-corp.com
HyperLink Technologies: www.hyperlinktech.com
Jefa Tech: www.jefatech.com
Maxrad: www.maxrad.com
Til-Tek Antennas: www.tiltek.com
WiFi-Plus: www.wifi-plus.com
The Absolute Minimum
Here are the key points to remember from this chapter:
Antennas are omnidirectional (all over the place) or directional (a focused beam).
If your Wi-Fi card or access point has a connector, you can easily add an external antenna.
Omnidirectional antennas don't cost very much, and they can add a great deal of range to your Wi-Fi network.
Directional antennas are usually used to broadcast from one point to another point; you need to think carefully about deploying directional antennas with your Wi-Fi network.