12-28-2010 02:41 AM - edited 12-28-2010 02:46 AM
Although these kinds of products aren’t usually found on shelves at big box stores like Best Buy, there are a number of solutions that can accomplish what you are looking for.
On the commercial end one of the best known companies for these kinds of solutions is called Ubiquity. They have a wide range of solutions that can provide multi-kilometre wireless connections. I have used their products to connect buildings wireless at distances up to 10Km away.
However there are many small manufacturers that provide these kinds products for less. As usual you won’t find them in stores, and are most likely to find them on online classified/auction sites.
Use the following search words on the above mentioned sites:
USB WIFI PANEL ANTENNA
USB YAGI WIFI ANTENNA
USB CANTENNA WIFI ANTENNA
If you don’t mind using basic tools and have the time to complete them, there are a number of Do-It-Yourself (DIY) projects out there. These are interesting projects as many are quite simple and inexpensive to build and can provide wonderful results. I have personally built some of these projects myself in the past.
Home Brew (DIY) Solutions
If you plan on buying an antenna I would choose, considering that this will be used outdoors, a sealed Panel style antenna with an outdoor tripod. Otherwise break out the toolbox and try one of the above DIY projects.
Have fun and good luck!