08-16-2002, 07:30 PM
|
|
Executive Editor
Join Date: Aug 2006
Posts: 29,160
|
|
How To Build A Tin Can Waveguide Antenna
http://www.turnpoint.net/wireless/cantennahowto.html
We've posted on things like this before, but this step by step was easier enough for even yours truly to follow it - and that's a good thing. Step 1: eat a hearty bowl of soup. Step 2: Read this article.
"Got no dough for a commercial antenna? Looking for an inexpensive way to increase the range of your wireless network? A tin can waveguide antenna, or Cantenna, may be just the ticket. This design can be build for under $5 U.S. and reuses a food, juice, or other tin can. I am not an electrical engineer, nor do I have access to any fancy test equipment. I've built some antennas that worked for me and thought I would share what I learned. I have no idea if this is safe for your radio or wireless network equipment. The risk to you and your equipment is yours." Source: External
|
| |
|
|
|
08-16-2002, 07:51 PM
|
|
Editor Emeritus
Join Date: Sep 2006
Posts: 3,060
|
|
I've always wanted to try to build one of these, just to see if I could. Maybe now I'll actually do it.
If you read the source article, there's a link to an annual contest that's held to see who can build the best antenna. It's really worth the read, especially the parts where the participants debate the relative value of cans from X Brand of Beef Stew versus Y Brand of Coffee versus Z Brand of Chicken Broth. They say the beef stew really IS the best, so you might want to start there...
|
| |
|
|
|
08-16-2002, 08:13 PM
|
|
Ponderer
Join Date: Jan 2007
Posts: 51
|
|
Okay maybe this is a stupid question, but how do I hook up my wireless network to the soup can antenna? Start from the Wireless AP or Router part please...
|
| |
|
|
|
08-16-2002, 08:14 PM
|
|
Intellectual
Join Date: Mar 2004
Posts: 116
|
|
A little bit of innovation can create some cool stuff!
|
| |
|
|
|
08-16-2002, 08:20 PM
|
|
Ponderer
Join Date: Mar 2004
Posts: 64
|
|
Same question as JJ... do most WAPs have connectorized attennae, or do you need to splice the new antenna in? Also, most WAPs seem to have 2 antennae, I assume for diversity reception, do you need to build 2 to get good reception?
|
| |
|
|
|
08-16-2002, 09:08 PM
|
|
Thinker
Join Date: Jul 2003
Posts: 382
|
|
Then there is the issue of having the two AP communicate to each other. I mean sure you can build up an antenna and fire the 2.4 Ghz anywhere you want, but to make use of it you're gonna need to send something back. Thus you need a second AP and antenna. What's the setup to get the two APs talking?
|
| |
|
|
|
08-16-2002, 10:55 PM
|
|
Editor Emeritus
Join Date: Sep 2006
Posts: 3,060
|
|
Quote:
|
Originally Posted by donkthemagicllama
Also, most WAPs seem to have 2 antennae, I assume for diversity reception, do you need to build 2 to get good reception?
|
Note that these devices are basically "wavelength cannons" and create highly directional signals. You're not boosting the overall strength, just focusing the signal and reception. So, one is enough, but it has to be fairly precisely aimed in order to work well. That's why you'll see photos of these things on camera tripods, so you can carefully aim them to that hammock 100 yards away on the beach.
|
| |
|
|
|
08-16-2002, 10:58 PM
|
|
Editor Emeritus
Join Date: Sep 2006
Posts: 3,060
|
|
Quote:
|
Originally Posted by JJ
Okay maybe this is a stupid question, but how do I hook up my wireless network to the soup can antenna? Start from the Wireless AP or Router part please...
|
I believe you need an access point with removable antennae. My Linsys one has two antennae that screw off. The naked connector on the access point is where the cable to the stew can connects.
|
| |
|
|
|
08-21-2002, 01:01 PM
|
|
Server Shogun
Join Date: Jul 2002
Posts: 89
|
|
Yes, you need an AP or client adapter that has an antenna connector. Most people seem to do this with the Orinoco cards, since they have a (very, very teeny and proprietary) connector. I've done this myself with Pringles cans, corner reflectors, homemade helical antennas from PVC and 12-gauge electrical wire, Orinoco client adapters, AirPorts (which use Orinocos internally), and Cisco APs with removable antennas (RP-TNCs).
If your client doesn't have an antenna jack, you can also create a passive waveguide -- make two antennas, connect them to eachother via wire, point one directly at your wireless device and point the other one wherever you're trying to get signal from. You'll lose an extra 3db through this arrangement, but it's better than nothing.
And for the record, I've found that the biggest bang for your buck is to buy some sheet metal from your local hardware store (the kind of sheet metal used for ductwork). Cut out a 4.9" tall by 9.8" wide rectangle. Bend it in the middle, so that you've got two 4.9" pieces. Roughly a 90 degree bend. Put it behind your client adapter. This is a corner reflector. It's the cheapest antenna you can make, and it produces astonishing results. (For best performance, the antenna inside your client adapter should be oriented vertically, and should be between the two plates of the corner reflector.)
|
| |
|
|
|
|
|
Linear Mode
