Here is how to build a high gain antenna for 2.4 gHz wireless networks. Several hams are experimenting with these devices in an effort to build a network. It is sometimes referred to as Hinternet or HSMM. My neighbor Jack, K8RT, and myself are also working on a neighborhood wireless network. As a result of these efforts, I have come up with my own version of the classic "cantenna" using 4 inch diameter aluminum dryer vent pipe, and a 4 to 6 inch pipe adapter. Although the basic design is the same as other cantenna type antennas, the materials I ended up using are a bit different. Preliminary results show a gain of 15 DBi. Not bad for less than $10 worth of materials!
A cross section diagram of the cantenna is below:
Location of the type N connector, and length of the antenna are critical. Below is a closeup with dimensions:
Here are the parts.
You will also need a piece of aluminum at least 4 inches in diameter (not shown).
Step by step instructions follow:
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| Snap the dryer vent tube together, and make sure the edges are flush at the seam. Measure 13.5 inches from this end, and cut the tube to this length. | Solder aprox. 1 1/2 in. of 14 ga. wire to the N Connector. I connect a spare N female to dissipate heat from soldering. |
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| Measure 1.75 inches from the edge of the vent. | Drill, then use a reamer to enlarge the hole so that the N connector will properly seat on the surface. |
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| Remove all of the burrs as a result of the reamer. | Drill 4 holes for mounting the N connector. I placed the heads of the screws in from the inside with washers. |
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| Measure a piece of scrap wire 1.25 inches, and cut it to length. | Using this wire as a measuring guide, cut the wire that is soldered to the N connector to the 1.25 inch length. |
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| Attach the 4" vent clamp snugly to the end. This forms the tube into a circle. Then mark the aluminum along the outside of the clamp. | Cut the aluminum so that it is slightly larger than the 4 inch tube. Then place it on the end as shown. |
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Secure the
plate with duct tape. Then place the 4 inch clamp over the duct tape
to secure it.
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Cut 4 vertical
slots in the 4 inch end of the 4" to 6" adapter. Slide the
dryer vent tube INSIDE the adapter, and secure it with another 4 inch
clamp.
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Your cantenna is now ready fo use. Enjoy!
The results are below. 15 Dbi
