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Researched and Edited by Nagi Hatoum |
For 2.4 GHz it is preferable that the can is between 70 mm (millimeters)
and 100 mm. The size doesn't have to be
exact. However, the Pringles can is really too small for good performance, Try
to get as long a can as possible. A smooth and shiny can is preferable.
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Step One |
Drill a 12mm in the side of the all metal can for the N connector.
The position of the N connector hole is determined by the overall
diameter (D) of the can. The placement of the hole and connect is very
important. Its location is derived from formulas that use the frequency that
the antenna will operate at and the can diameter. Measure the diameter (D) from
the inside of the can.
N-Female
chassis (panel) mount connector
Generic
Can Antenna Diagram
• 101.6mm diameter, hole
is 43.7mm from bottom (1/4 Lg)
• 95.25mm diameter, hole
is 47mm from bottom (1/4 Lg)
• 88.9mm diameter, hole is
52.6mm from bottom (1/4 Lg)
• 82.6mm diameter, hole is
63.5mm from bottom (1/4 Lg)
• 76.2mm diameter, hole is
95.25mm from bottom (1/4 Lg)
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Step Two |
Insert and solder a 30.7mm (1/4 Lo) piece of 12 gauge solid copper wire into the N connector to serve as your driven element (radiator). A piece of brass rod will work as well. The wire side goes in the can. The other side, where the cable attaches, goes outside of the can.
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Step Three |
The N connector is a threaded RF connector used to join coaxial cables. Solder (preferred), epoxy glue or use screws to attach the N connector/element assembly fitting to the can. Optional: Drill a small hole in the can just behind the N-type connector. Rain or condensation which finds its way into the can has an easy route out. The hole should not affect the performance of the cantenna.
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Step Four |
Attach one end of a pigtail to the N connector and the other end to your nic (wireless network card). Important: Unless you already have a wireless networking card with an existing jack for an external antenna, you will need to either modify your particular card by taking it apart and modifying it with delicate skilled soldering to attach an antenna jack (voiding your warranty), OR buy a new/used card that already has a built-in jack.
Pigtail is slang for a short piece of coaxial cable with two connectors. Pictured above is a pigtail with an "N" connector (the large one) on one end and a "MCX" connector (the small one) on the other end which connects a WiFi device to an antenna.
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Conclusion |
When aiming the cantenna, the polarization is important. Polarization refers to whether the driven element inside is pointing skywards (vertical) or sideways (horizontal). The direction of the driven element should match the antenna it is communicating with. That's all there is to achieve a 10db or better gain at 2.4GHz. Use either a high-quality female bulkhead (round) Type-N connector or a chassis/panel (square) Type-N connector. For an additional 5dB of gain use hardware cloth available at a hardware store to form a funnel 102mm at the throat and 406mm at the diameter with a length of 584mm. Solder or epoxy it to the open end of the coffee can.
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