For a course at the Technical University of Denmark (DTU) we were tasked to construct a high powered external wireless antenna. The course were given by Srdjan Capkûn, and were very well executed. The idea was to use the antenna to hack wireless networks from afar. As I must say that I am more than just a little interested in network security – and very interested in wireless security, we opted to go All-In on the project.
To get the maximum gains we bought an old satellite disc, some canned pineapple, various cables, copperwire and bits – and got cracking. The idea behind the “cantenna” is to have a very sensitive network card with an external antenna placed in the focal point of a contraption that focuses the radio waves in one direction.
The construction process of the cantenna from scratch to finished product
With the cantenna we could sniff networks from multiple kilometers away. The limiting factor in our case turned out to be line of sight. As the cantenna’s signal is very directional and easily obstructed by leaves, buildings and the like, we needed a good vantage point. If you are in located in the city, in a skyscraper, then this beauty gives you free wifi like nothing else.
Our vantage point. 2.4 kilometers down that road we picked up the signal from an Compaq IPAQ we conveniently had placed there. It might have gone further, but we ran out of road 
