Homemade antenna redux May 6, 2009Posted by rururudy in how-to.
Tags: diy, free ruler, how-to, wireless
Am I still making homemade antennas? Can’t think of anything new? Years ago, I gave a dorkbot talk on a can antenna. OH MY! I just looked at Karen’s old photo of me — I have the same facial hair after 7 years — I better shave it off before I finish this post — don’t want to be in a hairy rut!
I did an 802.11g test last week and got 10Mbps across the street with the can, but the goal is to convince KQED to replace their 1990’s T-1 lines with a wireless link. It’s got to look a bit better than tin cans, so I went down to Complete Fabrication and scrounged some tube out of their yard. (MonkeyBrains.net hosts their website, and Ryan is a great guy, so he let me grab some three and a quarter inch aluminum tube.) Jay Brommel welded the tube pieces onto some angle bar, I drilled some holes, and tonight I added the ‘element’. Here is the final product:
The measurements are thanks to the ‘How To Build A Tin Can Waveguide WiFi Antenna‘ instructions.
(The Ruler is thanks to Alameda County — you can get not only a free ruler, but your soil, paint, etc tested for FREE with a home lead-test kit — fun! You should try it.)
The goal is to plug these things into a wireless router (one with detachable antennas) with ‘pigtails’ that have N connector fittings on one end and wireless router fittings on the other. N connector’s are easy to find … I picked mine up in Berkeley at Al Lashers, but the pigtails are close to impossible to find outside of the Internet (I get mine on eBay). Wireless gear has either a RP-SMA (small) or RP-TNC (slightly larger) jack.
Do use the pigtail, I needed to pop-rivet the N connector onto a flat spot on the tube — filing down the soft aluminum gave me a stable spot.Using my trusty soldering iron (with inline kill-switch), I soldered a length of scrap copper onto the N connector. I trimmed the wire so that it was exactly 1.21″ (30.7mm) above the white base area (if you want to know why, check out the Waveguide URL above).
Tomorrow, I go over and try these antennas out, wish me luck!
Test speed with new cans
Test the omni-directional antenna (also homemade using these instructions)
Set up multiple antennas and try 802.11n — do I need 2 cans? figure out MIMO
FYI: The remote side is set up as a client bridge, while the connected-to-the-Internet side is set up as an Access Point. That lets you span the LAN from one building to the next.