Questions

Cantenna

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Cantenna

ksmith
We are supposed to build a cantenna for the one class I am in. According to the paper we received all the parts should end up costing us under $10, however given the time limit we have on this project I have to use all local stores and pay a lot more.

My main issue is that no guide tells us exactly how the cantenna is hooked up to the computer after the can is made. It looks as though it need s to be soldered onto a wireless card, but that a lone would make this a lot more expensive then I am will to go.

Does anyone have experience building one? Can you possibly point me in the right direction?
Thank You
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mjd420nova

First you need to determine what the impedance of the cantenna is supposed to be, this would be in the specs for the appropriate WIFI card you'll be using. Then working from that, select the gauge wire you'll be using and it's resistance per foot would give you the length of wire to use and then decide the size of can to use. I've made a few out of toilet paper rolls which is pretty close to the size used commerially, but maybe a paper towel roll or maybe a little larger paper coffee cups. The form must be non-metallic.

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You will have to define what you mean by Cantenna. It loosely defines two different styles of antennas. There is the Pringle's can style and the Tomato can style. This link talks about both and the requirements you can use to build them.

http://www.turnpoint.net/wireless/has.html

You also did not mention what style of wireless network adapter you have, I am assuming that there are no normal coaxial connectors visible on the PC board. I would suggest not soldering any wires to the adapter until you are sure which wires are the ground and active element. Most pc card wireless network adapters have DIY antenna install instructions available, you may want to check the "net" to see if there is one available for your specific adapter.

I favor another option that I thought I might mention. I am not sure if you are allowed to use this approach, but I prefer to use a USB dongle wireless network adapter, installing it at the focal point in a tin can reflector. It removes the RF loss from coaxial cable and removes the issue of how to connect the leads. These links help explain the details.

http://www.educypedia.be/electronics/Wlan-antenna/cantennadongle.htm

http://members.cox.net/tulsaalstons/Documents/Tin%20Cantenna%20Made%20With%20Compact%20-%20Dongle%20USB%20Wireless%20Adapter%20.htm