Posts Tagged ‘wifi’

DIY Friday: Convert Your Primestar Dish to 802.11

Friday, August 4th, 2006

What do you do if you need to get WiFi access in a relatively remote location — say, a distant outbuilding? Waiting for WiMAX might mean waiting a long time in rural areas. Why not just grab an old Primestar dish, a tin can, and some coaxial cable, and rig up your own WiFi antenna?

A student at Walla Walla College explains: 

 It is easy to make a surplus Primestar dish into a highly directional antenna for the very popular IEEE 802.11 wireless networking. The resulting antenna has about 22 db of gain, and is fed with 50 ohm coaxial cable. Usually LMR400 or 9913 low loss cable is used if the source is more than a few feet from the antenna. The range using two of these antennas with a line of sight path is around 10 miles at full bandwidth. I must stress the line of sight part though. Leaves really attenuate the signal.

The "things you need" can be found easily by any aspiring MacGyver:

   1.  A Primestar dish.  (You may use any old dish, but if it is bigger than the Primestar the gain will be higher, and it may not be within the Federal Communications Commission rules for use within the United States.  In fact I have come to find out that there seem to be several different dishes that Primestar used, and I am only sure that the one I used, pictured above, used with the ordinary Wavelan or Airport transceiver card is within the effective radiated power limits given by the FCC.)
   2. A juice can (about 4 inches in diameter and at least 8 inches long).
   3. A chassis mount N connector.
   4. You will also need a "pigtail" connector which has the proprietary Lucent connector (for the PCMCIA card) on one end and an N connector on the other. The pigtail can be obtained from a number of online stores for $35 to $40.

Once assembled, you’ll want to brace the highly directional antenna securely against the wind. 


City Wi-Fi, Green Wi-Fi

Wednesday, August 2nd, 2006

It’s been a long time since I blogged about my enthusiasm for municipal wi-fi, but news from Boston brought the subject back to mind again.

Wi-FiBoston’s plan to create a citywide wireless Internet network entered a new phase yesterday as Mayor Thomas M. Menino named former high-tech executive Pamela Reeve to lead the search for a non profit corporation to build the network.

Reeve, a member of the mayor’s Wireless Task Force and a former chief executive of software company Lightbridge Inc., also will talk to businesses, foundations, universities, and hospitals in an effort to raise between $16 million and $20 million for the project.

The money would be used to blanket city neighborhoods with fiber-optic cable and radio transmitters that would beam WiFi signals, enabling laptops, handheld computers, cell phones, and other portable devices to connect to the Internet at high speeds anywhere in the city.

As noted at GigaOm, this model is unlike any other in blending resources from government, business and non-profits. Can it work? Who knows, but if it does the next step might be to combine it with an idea like One Laptop Per Child movement, but with a domestic focus. Nigeria just ordered (and payed for) 1 million of the wireless-equipped laptops. It could happen in the U.S. too — wi-fi access and low-cost wireless laptops opening up new opportunities for a lot of kids.

And as long as cities are launching wi-fi networks, the might want to consider making them green too.

Green Wi-FiThe technical concept behind the Green Wi-Fi network is fairly simple. Each node in the network consists of a battery-powered router and a solar panel to charge the battery. The nodes are mounted on rooftops, and the network’s Wi-Fi signals are transferred over a grid using a wireless network standard known as 802.11b/g.

The first seed money has arrived, enough to produce and test prototype nodes. It came from the One Laptop Per Child initiative (OLPC), which aims to construct a $100 laptop to be distributed to children in developing countries. OLPC showed immediate interest in the Wi-Fi initiative, Pomerleau said.