Wireless Hacks

Pirouette Can Waveguide

Build a simpler, higher-gain antenna-in-a-can.

Since the Pringles can story was published, I have received a phenomenal amount of email from people who have tried it for themselves. While some people simply enjoyed making a recycled antenna out of a piece of trash, many people told me “you know, that’s not a bad design, but some friends and I found a better way to do it...”. One such person was Gregory Rehm. He took my Pringles can design, and another coffee can design that I was working on, and pitted them against his own designs (including a 40 oz stew can) in a Wireless Shoot-Out Battle Royale. His experimentation and excellent analysis is documented on his web site at http://www.turnpoint.net/wireless/has.html. It is very entertaining to read (and in case you’re too filled with suspense to wait until you can check his site, his stew can won by a mile).

As it turns out, it is much simpler to make a tin can waveguide antenna than to bother with cutting pipe and spacing washers apart on all-thread. He has an excellent how-to posted online at http://www.turnpoint.net/wireless/cantennahowto.html, complete with photos, diagrams, and formulae.

Another common can that approaches the ideal diameter for 2.4 GHz is the Pepperidge Farm Pirouette can (see Figure 5-5). It makes a much simpler, sturdier, and more efficient antenna than a Pringles antenna, and the best part is, you get to eat the cookies!

Figure 5-5. The Pirouette “cantenna.”

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