$10 Super Duper WiFi Antenna
There are sometimes that a single bar of WiFi service isn’t going to cut it. You can see the access points near you, but the signal is just too weak to get you any access. Before you go out and spend $100’s for pringle can like antennas give this $10 alternative a spin.
Items needed: some 35-mm foam (like the kind desktop and laptop PCs usually come with), some solid-core copper wire, a small brass plate, and multiple BNC connectors. Then follow the directions in the video and you’ll have a super powerful directional antenna that should get you better gain that that external antenna your card came with.
Remember, this works as a directional antenna so you need to have it pointed in the right direction to get a strong signal. Just sweep it around slowly until you can lock down a super signal then surf away!

This is great, but say I wanted to create a transmitter, does the same principle apply? What changes would I need?
@Rutherford – It does apply. The exact same principle applies. The only problem with the above example is that you would be build a directional transmitter so who ever is connecting has to be in line of sight to the antenna. You would be better off with an omni-directional antenna.