Tuesday, January 10, 2012

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.

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.




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.)



Links:
http://pe2er.nl/wifisector/ - Erwin Gijzen's homepage
http://www.digdice.com/12dbi-180degree-sector-wifi-antenna/ - estqwerty's digdice wireless (awesome blog)

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