What Tin Can Antennas Are For

Chapter List

Chapter 15: The Tin Can Bandwidth Expander Project

Chapter 16: Bridging Two Networks

Chapter 17: The Parabolic Mesh Reflector Project

Chapter 18: Going Wardriving

Chapter 19: NetStumbler's Log Files

Part Overview

Your network is done. What next? The only thing more amazing than the power of a $50 microwave network data radio is what some people have managed to do to enhance them, often with nothing more than (as my sister once put it) kitchen trash.

Yes, kitchen trash. I've built Wi-Fi gain antennas out of coffee cans, spaghetti sauce cans, and (moving outside the kitchen a little) tennis ball cans. You can even make a serviceable gain antenna out of a foil-lined cardboard soup or juice box of the correct size. If you have any skill at all with a soldering iron and an electric drill, you can do it too. I'll explain how in gruesome detail in Chapter 15.

One of the primary uses of gain antennas lies in establishing 'data bridges' between buildings, over distances that may measure in miles, all using a few thousandths of a watt of microwave power. In Chapter 16 I'll show you how to create a Wi-Fi bridge using two access points and a pair of gain antennas of your choice. You don't need to use kitchen trash-gain antennas can be purchased new, often for less than $50.

Even if you don't need the 'reach' of a true gain antenna, you can extend the range of a Wi-Fi access point or external client adapter with a little scrap of º' hardware cloth, shaped into a parabola. I've found them great for 'shaping the field' and finessing dead spots, and you can learn all about that in Chapter 17.

Finally, with a piece of free software, you can throw your laptop in the back seat of your car, slap a mag-mount Wi-Fi antenna on the roof, and take a Wi-Fi census of your neighborhood by just driving around. The new hobby of wardriving has been slandered up and down by those who don't understand that it's not about breaking into networks at all, but simply about discovering where those networks are. (Wireless networks can't really be hidden, and most broadcast their presence every tenth of a second.) This can be useful in a number of ways, especially if you find yourself supporting wireless access to a company network. I'll provide the full scoop in Chapters 18 and 19.

Truthfully, Part 4 of this book is about having fun with Wi-Fi, and fun is the best way to go from being a neo to being a guru. Got some kitchen trash? How about throwing some microwaves? (Talk about recycling…)