Wireless Antenna Project
We have a team of 2 people to build a directional wireless antenna (cantenna) for my IT103 Networking class. We will be using a can and a special device called a ‘radiator’ that Rudy will supply. We will work together to research and build the device. We will individually create a ‘build’ web log that chronicles the experience.
The size, shape and design of the can is our decision. There are scientific principles at work so we used a cantenna calculator to do a little research before we broke out the drills and spray paint!
Partner: Thida Paing
Project (Individual vs. Partners)
We need only one cantenna for the team, but we decided to build our own cantenna individually and choose the better of the 2 based on: 1) Efficiency (strength – who had the lower test score?) 2) Appearance (Design – most creative for best rating by classmates). Then, we will turn in the best cantenna to Rudy to test for our grade.
Choosing a can based on calculation of diameter vs. frequency and wavelength relation calculator
Based on research, a can with a diameter range of 3 to 5 inches would give the best performance. The diameter of my can was 4.25 inches.
Materials and tools used for the project:
- Safeway Chicken Broth can (diameter 4.25 inches)
- Can opener
- Drill press
- Metal File
- Soldering iron
- Measuring tape
- Scissors
- Black spray paint
- Metallic tape
Can calculations:
| Can Diameter in inches: | 4.25 |
| Lower Cutoff Frequency Check in MHz (make sure < 2412MHz for 802.11b) | 1627.59 MHz |
| Upper Cutoff Frequency Check in MHz (make sure > 2412MHz for 802.11g) | 2125.85 MHz |
| Guide Wavelength | 6.51 inches |
| ¼ Guide Wavelength
(Antenna element to sealed base) |
1.63 inches |
| ¾ Guide Wavelength
(Antenna element to open front end) |
4.88 inches |
Measuring and drilling a hole for mounting radiator
Based on the calculation, the distance of where I should mount the radiator from the rear of the can is 1.63 inches. I marked a spot on the can at 1.63 inches from the rear of the can. Made a punch mark with a file and drilled about ½ inch hole.
Building Stacey’s cantenna
- Chose a can based on calculation of diameter vs. frequency and wavelength relation calculator: Safeway Chicken Broth.
- Measured and punched a hole with a file at 1.63 inches from rear of can.
- Drilled hole larger (1/2 in) with drill press for inserting radiator.
- Decorated the cantenna by painting it black and adding lightning bolts.
- Friday’s initial testing of signal was 84 @ 310 feet.
- Added another can for length to see if that made the signal any better.
- Saturday’s testing of signal was 84 @ 310 feet (so the extra length didn’t help).
- I removed the radiator and sanded off the black paint where the radiator connected and retested – the signal was now 82 @ 310 feet (so removing paint helped).
Partner Thida’s work:
Preview of work: Process of Building Thida’s cantenna
- Choosing a can based on calculation of diameter vs. frequency and wavelength relation calculator
- Measuring and punching a hole for mounting radiator
- Extended version for effectiveness
- Initial testing
- Installing tripod stand
- Decorating the cantenna
Partners (Stacey and Thida):
Friday May 29th testing
Stacey’s cantenna – testing result was 84 @ 310 feet distance.
Thida’s cantenna – testing result was 80 @ 310 feet distance.
Saturday May 30th testing
Stacey’s cantenna – testing result was 82 @ 310 feet distance.
Based on the effectiveness, we chose Thida’s cantenna to turn in for the project.
Cantenna history:
A cantenna is a directional waveguide antenna for long-range Wi-Fi used to increase the range of a wireless network.
The term cantenna originally referred to a product sold by Heathkit Co. and was used by radio amateurs. The original design was based on a Pringles can but can be made using various sized cans. The best is a can between about 3″ and 3 2/3″ in diameter. The size doesn’t have to be exact. Others have reported good results with cans that are 6″ in diameter. The Pringles can is really too small for good performance, however. Try to get as long a can as possible. The old fashioned fruit juice cans should work well.
What I would like to do now:
I found this project very easy to do; I will be purchasing a radiator so that I can use my can.
I also found information on how to create a broadcast antenna using a can.
