Abstract

Exploring low cost wireless
With an initial 500 students and one faculty equipment : the cantenna. A case
of Education at its first intake, the University study of Mzuzu University.
now has over a thousand students and five faculties. Rachel Chavula
each student walking in the corridors of the University. As the major book store, the Mzuzu University, Malawi.
college Library serves students and members of staff from all disciplines. Abstract
However, books are not enough for all to use, besides that some books have been on The Internet has irrevocably become a very important tool in development. As a platform information. In a technologically advancing for information sharing, communication, world like this one, the Internet has proved socialization and entertainment; it is to be the best supplement to a book as it is increasingly becoming a must to have the easy to get updated information from it. facility whether in a home, school, hospital, the same time remotely. This is unlike in the case of one book against a group of say a In recent years we have seen the invent and widespread use of wireless Internet as University at times. It is in this regard that compared to wired Internet. It is said that wireless technology is more handy than the wired technology as it is easy to deploy and more convenient due to its mobility. Despite the fact that the fraction of people with access to the Internet is far higher in students. Students are introduced to the rich than poor countries, it is inevitable to computer and the Internet through computer accept the fact that developing countries like Malawi, certainly need the Internet in order to bridge the digital divide. Of particular interest in this paper is the use of the Internet in the education sector and Internet Access
specifically the case of Mzuzu University. The paper focuses on one of the challenges Internet access at the University is via a that exist at the University as regards access to the Internet which is poor signal reception in most areas and then explores of wireless links. There are five hotspots one of the possible solutions. The proposed within the campus. The equipment used is solution leans towards development of low from Mikrotik, and the antennas gain are in cost equipment and in this case the expected to cover a radius of at most 10 kilometres. However, this is not the case as Introduction
the signals cannot be detected across the entire campus whose span is less than four Mzuzu University is located in the northern region of Malawi, in a city called Mzuzu about three hundred and sixty-seven kilometres away from the capital city, Lilongwe. The University was established by an Act of Parliament in 1997 as Malawi’s second national (public) university. The first students were admitted in January 1999 [7].
Infrastructure
There are five computer laboratories at the Possible
Solutions
University. One is strictly for postgraduate students and has seven computers which architecture of the wireless system.
Students use these at no cost. Four laboratories are open to undergraduate students but two of these operate on a commercial scale. One of these is run by the University and the other was an initiative from the American Embassy who support its computers in these two commercial laboratories.
Train technical personnel on Bandwidth management.
What is called the ICT Lab is solely for learning purposes mainly for students pursuing the Bachelor of ICT program and is open to other departments for courses like wireless Internet which is low due to poor Statistics. There are at least forty computers campus, I thought of making cantennas to in this laboratory and all have access to the Internet. The other laboratory does not offer free. There are about twenty computers in this laboratory. Antenna
Problems
There are about a hundred and twenty
An antenna is a very important component of communication systems. It is a device students. This translates into a ratio of about used to transform an RF signal travelling on 1:10, which reflects how difficult it is for a a conductor into an electromagnetic wave in student to access the Internet. Furthermore, when you consider the monetary aspect attached to the other two laboratories; the access level narrows down even further.
Cantenna
For students that have personal computers it is easier to have access to the wireless Internet using their computers; however, a greater part of the student village and most wireless network [8]. It uses a tin can as a waveguide and a short wire soldered on an signals at all. This is due to the low capacity N connector as a probe for coaxial-cable-to- of the links coupled with obstructions from waveguide transition. It can be easily built at trees, buildings and other objects. This then just the price of the connector, recycling a makes it also difficult for students to access food,juice, or other tin can. It is a directional the facility within the comfort of their rooms antenna, useful for short to medium distance point -to-point links. It may be also used as a feeder for a parabolic dish or grid [1].
There are also emerging constraints of bandwidth management. The network gets so congested especially when there are many users and this slows down the Why a cantenna?
the guide wavelength. The probe for coaxial cable to waveguide transition should be A cantenna is more affordable as compared positioned at a distance of about 3.05cm at to the antennas from the shelf. It can be built 2.4Ghz, which corresponds to 0.25 of the easily at just the price of the connector, recycling a food,juice, or other tin can. An antenna from the shelf would cost about 200 Euros, yet a home made cantenna that Tools required
would do the same job would cost about 2 Euros.
Building a Cantenna
4 cm of copper or brass wire of 2 mm of diameter.
Procedure
should be within the range as specified in the illustration below.
the bottom of the can and mark the point.
3. With a small diameter drill bit, make a hole at the center of the plate. Increase the diameter of the hole using bits with an increasing diameter. The hole should fit exactly the N connector. Use the file to smooth the border of the hole and to remove the painting around it in order to ensure a better electrical contact with the connector.
Note that, not all cans are good for building an antenna because there are dimensional constraints. The acceptable values of the feed are between 0.60 and 0.75 wavelength in air at the design frequency. The length of the can preferably should be at least 0.75 of Results
4. Smooth with the file one end of wire. Having built the cantenna, I experimented on a few areas where the signal was very poor around the campus. I connected the cantenna to a wireless card using the pig tail and pointed it towards the main antenna.
central pin of the connector. Keeping the wire vertical with the Through rotation, I managed to get at an angle where the signal was good; then, I the nut onto the connector. Trim the wire at 3.05 cm measured from thebottom part of the nut.
leaving the washer in place. Insert the connector into the hole of the can. Screw the nut on the connector from inside the can.
wrench to screw firmly the nut on the connector. You are done! The gain for this antenna will be in the order of 10 to 14 dBi, with a beamwidth of around 60 degrees. This is ideal at 2.4Ghz.
Operation – Get Connected!
Using the cantenna
The ICT club is a students' club for those To use the cantenna, a pigtail is needed. This is a cable that connects the wireless card or access point to the cantenna. One end will have an N-type male connector, to interest in building cantennas. It is expected connect to the cantenna, the other end will that this will act as a catalyst to carry out more experiments on the cantenna so as to improve its performance further. The only This antenna has linear polarization which means that rotating the antenna will affect students is getting a pig tail and connectors. the strength of the signal. It is good to However, it suffices to say that these are not watching the signal strength on the PC to Now that the ICT club has plans to raise funds to buy parts such as these, things should get better soon. Already with the few cantennas made, we call this Operation-Get Connected and it is just the beginning. Professor Fr John Ryan and Mzuzu University ICT Club for their support and Recommendations
More cantennas must be built to increase the range of the wirelessInternet on the campus which is not References
far reaching. This is feasible, as the cost of production is low and that it [1] Flickenger Rob et al., WIRELESS the hunger for research on developing other low cost wireless [2] Flickenger Rob et al., How To Accelerate Your Internet, INASP/ICTP, stakeholders should consider funding student clubs such as the [3] National Research Council of Malawi, [4] “How to Build A Tin Can Waveguide WiFi Conclusion
The cantenna is a very good solution to the problem that exists at the Mzuzu University of poor signal reception in most areas due to obstruction from trees and other objects. Its low cost of production yet commendable performance renders it a good choice as an alternative to the “expensive” antennas one Further research is needed on testing the performance parameters of the cantenna so as to come up with the best performing cantenna. Such low cost infrastructure can be adopted in developing countries if we are to increase the number of Internet users. Of course that calls for a balance of scales between quality equipment and cost; which Acknowledgments
I would like to thank the International Center [9] Tauritz et al., CANTENNA BUILDING,SIG for Theoretical Physics (ICTP) in Trieste, Italy for giving me the opportunity to attend the school on wireless networks, where my [10] Flickenger Rob, Wireless networking knowledge base on wireless networking was architecture, School on wireless networking Zennaro of ICTP, Doris Nyirongo who is senior technician at the Mzuzu University,

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