Low Cost Home Brew Waveguide Antenna For 802.11b
Wireless Networks And Other 2.4GHz Applications
Here is a do it yourself (DIY) project that is an inexpensive way to increase the range of your wireless network or cordless phone. This idea is not new and has many names such as shell cell, cantenna, bazooka antenna, canned antenna and tin can annie. We like to call it a recycled waveguide antenna. Whatever you call it, it is an interesting project that takes very little time and very little money. Total time should be under an hour and total cost under $10.00, even if you don't have an electronics junk box at home. While this has worked very well for me, there is a certain amount of risk to equipment any time you experiment. We assume no responsibility or liability. In order to do this, you will need to gather a group of materials needed. Call it scavenging or preparation; it should not take long. For one recycled dish, you will need:
1. 1 - N-Type Female chassis mount connector.
2. 1 - Copper 12 gauge wire about 2 inches long.
3. Several small nuts and bolts or other mounting hardware for mounting the connector.
4. 1 - Can.
The N type female chassis mount connector is typically used in radio applications. Hams and electronics hobbyists may have one hiding in the junk box. Most came so that they mount by way of four small screw or nuts and bolts; some had other mounting brackets. We will mount this to the our recycled directional dish. One side is N-female for connecting the cable from your wireless equipment. The other side has a small brass stub for attaching the small piece of wire with solder.
The can that worked best for me was 3.25 inches in diameter. The other people trying this have used other sizes between 3 inches and 3.75 inches with success. Some tried cans 6 to 7.5 inches in diameter. They also worked. While there is no exact length of the can cylinder, the longer the can, the better the performance but the more directional it is. The calculator will provide the approximate numbers for actual installation of the connector into the side of the can cylinder. Enter the diameter of the can and click on Calculate. Drill or punch holes in your can to mount the connector the length of the 1/4 wave guide from the closed end of the can. The center conductor that will be soldered to the brass stub cannot ground against the can. The shell of the connector does ground to the can. Before actually mounting the connector, prepare the 12 gauge wire to be soldered onto the brass stub of the connector. The length from the connector that worked best for me was 1.21 inches. It should be perpendicular to the shell of the cylinder when mounted in the connector and the connector to the can. Hook up your cable from the wireless device external antenna port, point the antenna at another device and test the antenna. This is a linear polarized antenna. The direction it is pointing and the vertical angles are important. Generally line of sight (LOS) is a good rule. Most all wireless networks have tests for signal strength. Test prior to the project and after the project. Experiment with angles and directions. Also experiment with can sizes and perhaps positioning of the connector. Good luck. We would love to hear from you with results.