The 5 foot Antenna

While at one of the many “security” (hacker) conventions I visit, there was a vendor selling external wireless cards, but not just any wireless devices but one of the most powerful ones currently made. The Alfa 500mW is not only powerful but you can add any antenna to it you may want.
I know you’re asking why would you want an external wireless card when your laptop has a perfectly good one inside it. The truth is, I didn’t need it but there are a couple reasons I wanted it: First, many of the wireless cards that come with your laptop don’t have drivers for linux, which I’ve been slowly playing with over the last couple months and Second, the default cards don’t have some of the extra functionality I was needing.
This card comes with a small antenna with power measuring 2dBi, I wanted something that would reach for a couple blocks, not just my neighbors, so the search was on for a high powered antenna. Searching all over the web I found many laptop omni antennas but all were around 9dBi, I wanted more power. Finally after weeks of searching I found an antenna that was 15 dBi, one of the most powerful i’ve seen with out being directional (you have to point it to the direction of the access point). I placed the order and waited…. The shipping day had come and I couldn’t wait to get home and hook up my new antenna and see what kind of trouble I could get into, I get home from work, check the front porch and I see a huge tube sitting there. Opening the tube I find that my perfect antenna is actually a 5 foot external antenna (no wonder it’s so powerful).
I’ve since ordered a smaller 10dBi laptop antenna for travel and since it’s a bit hard to sneak around with a 5 foot antenna. I also decided to keep the large antenna to play with and if I get tired of it I can always donate it to a school or church that needs to push wireless across a yard (or block).
So just how powerful is this antenna? Well with the internal antenna in my laptop, from my back porch I can see 3 wireless networks, including mine. With the huge antenna, I can see 20 different wireless networks.
Soon I’ll post just how easy it is to hack access to your wireless network, but till then, check your wireless router at home and make sure the security is set at WPA, if it’s WEP it can be hacked in a matter of minutes.

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