An Antenna Made From a Tin Can
Wireless Communication
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 The so-called cantenna is a cheap and efficient tool to help access Information and Communication Technologies (ICTs). The best cans are those used for seed oil and have a screw-on antenna and a short brass wire. Working like regular antennas, cantennas only cost around $2.50 to build. Rachel Chavula learned about them during an internship at the International Centre for Theoretical Physics (ICTP) in Italy. Since then, the 22-year-old has been trying out cantennas on her Mzuzu University Campus in Malawi. She will present the “making of” in a hands-on demo session.
The Origin of the “Cantenna”
Founded in 1964 by Nobel Laureate Abdus Salam, the ICTP Centre operates under a tripartite agreement between the Italian government and two United Nations agencies, UNESCO and IAEA. Its mission is to foster advanced studies and research, especially in developing countries. While the name of the centre reflects its beginnings, its activities today encompass most areas of physical sciences, including applications. In 40 years, more than 100,000 scientists have visited the centre to conduct research or participate in training seminars.
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 ICTP for three years and collaborated with other instructors to write "Wireless Networking in the Developing World," a how-to manual available for free on the Internet.
http://en.wikipedia.org/wiki/Cantenna
The tool Rachel Chavula will demonstrate at eLearning Africa is easy to build, costs no more than the price of a used can with the requisite dimensions, and requires only a small copper wire and a connector. Simple versions have been widely used in do-it-yourself communities worldwide. Cantennas 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.
The motivation behind fostering this tool comes from the fact that Internet access is usually limited in developing countries. Mzuzu University has been utilising this tool, as Internet signals do not travel far and hence, there is poor reception in most parts of the university campus. Using the cantenna has made a difference – by extending the range of the wireless network, yet at a low cost.
Initially, Rachel Chavula worked with the cantenna in Trieste, Italy. Since 1989, the radio communications unit of the Aeronomy and Radiopropagation Laboratory at ICTP 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 centre believes that if you help research scientists stay connected, there is more chance that they will stay in their countries, avoiding a so-called brain drain of educated talent.
Rachel Chavula
Rachel Chavula: “I find the cantenna very applicable to areas like Africa, where cost of materials is a hindrance, yet there is the need to bridge the digital divide. The cantenna will do the same work as the antennas from the shelf. I have been working on how to optimise its performance and it has been a great experience.”
April 7, 2009
 Newsportal: Technology Developments
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