In my spare time I build and test various wifi designs found on the Internet. I am using this knowledge to build cheap and simple wifi hot-spots that can be setup with very little technical knowledge. I believe that wifi should be in all places people frequent. From the mall, the grocery store, to downtown areas, free wireless Internet should be everywhere.
Showing posts with label sector. Show all posts
Showing posts with label sector. Show all posts
Monday, January 16, 2012
Sector Antenna version 2 teardown
I decided to redesign the sector antenna backplate/reflector to make it more robust. As you can see the hot-glued antenna standouts were inadequate to deal with even transport vibrations. I have decided to use nylon screw anchors the next time. The main differences between this and version one are as follows. Most noticeable is the copper coating on the reflector assembly. I used copper gasket spray which can be purchased at automotive parts house. The second difference is the copper insulator at the center of the antenna element. A few other people have used this method, I found it was far superior for holding everything in place and aligned. There are no other modifications done.
Tuesday, January 10, 2012
Sector Antenna version 2
After making the one sector antenna and getting a taste of the performance possibilites, I went ahead an immediately made 2 more. This time I have fewer pictures of the elements and balun area and more exterrior shots. I will say there are some issues with my initial design for the reflector backing and n-connector mounts. Therefore I will be build another two with a few design modifications I made. Here are the pics of what I have now, when I tear these units down to rebuild them, I will upload pics of the element and reflector assembly.
Sector Antenna Build version 1
The goal here was to replicate the work of others to create a low cost wifi sector antenna from off the shelf components. In many places in the United States do not have access to public wireless internet services. Maybe my interest in the subject will help others here in the States' to jump on the municipal public wifi bandwagon as the rest of the world has. Credit to Erwin Gijzen and Dragoslav Dobricic for their designs. More links to others projects below.
This is my first attempt. I used material that was easily available. The total build time was 8 hours, but I'm sure it can be cut down significantly with better fabrication techniques. I will show details on my next build.
The Finished product is amazing. I have full wireless signal in an approximately 130 degree arc at 600 feet from the antenna, using the Cisco iphone app, CIST. I had on average 38Mbps at 300 feet and 26Mbps at 600 feet. The Antenna was mounted at 20 feet above the ground at a 10% downward tilt. Here is the test setup. Linksys WRT-54GS v6 with dd-wrt v24 SP2 micro build firmware with hot-spot mode. I used b/g mode with auto channel selection. The transmit power was set to 125mw. (Note: The router antenna selected is the one closest to the power. This means there is a length of lmr-195 ~17cm long between the motherboard and the connector. I chose this method to test the low end of the performance envelope first.)
This is my first attempt. I used material that was easily available. The total build time was 8 hours, but I'm sure it can be cut down significantly with better fabrication techniques. I will show details on my next build.
Length: 455mm, width: 62mm
The balun, 40.7mm length
The n-female connector
Standard RG-58U. This is all I had at the moment. Use LMR-400 if possible.
Links:
http://pe2er.nl/wifisector/ - Erwin Gijzen's homepage
http://forum.wirelessnederland.nl/viewtopic.php?t=8128&highlight= - Wireless Netherlands
http://www.digdice.com/12dbi-180degree-sector-wifi-antenna/ - estqwerty's digdice wireless (awesome blog)
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