February 28, 2006
Introducting the Cantenna
A physics research institute in Trieste, Italy is using a low-cost but effective tool to bolster communications in developing countries: the tin-can antenna. Made from a can (the best are those used for seed oil), a screw-on connector and a short brass wire, the "cantenna" is promoted by researchers as a cheap and efficient tool to amplify access to information and communication technologies in some of the world's poorest and often most remote areas. Cantennas work like regular antennas but cost around $2.50 to build. Those purchased in a store can cost several hundred dollars.
They are directional antennas and can be used for short- to medium-distance point-to-point links. They can also be used as feeders for parabolic dishes. That means that by aligning a series of cantennas, it is possible to receive signals from a distant receiver using one or more repeaters, which send, amplify and redirect radio waves, and send signals to remote areas.
Since 1989, the radiocommunications unit of the Aeronomy and Radiopropagation Laboratory at the Abdus Salam International Center for Theoretical Physics in Trieste, has been working on technology to bring the third world into touch with the first, and in 1998 it shifted its focus to wireless networking, a rapidly growing market sector in the developing world.
The Institute of Telecommunications in Geneva in collaboration with the school in Trieste has attracted dozens of top engineers and scientists from emerging countries eager to learn low-cost techniques that will connect universities and hospitals, and eventually even remote villages, back home. The school is a natural offshoot of the International Center for Theoretical Physics, which was founded in Trieste in 1964 by Abdus Salam, a Pakistani who shared the Nobel Prize in 1979 for his work in particle physics, to advance scientific expertise in the developing world. In 40 years, more than 100,000 scientists have visited the center to conduct research or participate in training seminars.
The center believes that if you help research scientists stay connected, there's more of a chance they'll stay in their country, avoiding a so-called brain drain of educated talent elsewhere. The 2006 wireless networking course, which had participants from more than a dozen countries, including Venezuela, Rwanda and Iran, ended last Friday.
The cantenna has been around for years, but in Trieste it was fine-tuned by Rob Flickenger, the co-founder of NoCat, a California-based wireless company that promotes open-source software. Flickenger has taught at the school for three years and collaborated with other instructors to write "Wireless Networking in the Developing World," a how-to manual published in January and available at no cost on the Internet.
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A Pratical Guide to Planning and Building Low-cost Telecommunications Infrastructure
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