Most satelite dishes are fixed because the satelite is fixed in space. In order to have it track a source, the receiver has to be able to differentiate between source left and source right, or up and down if you want two degrees of freedom. An optical system would be the easiest to implement because it is easy to shade the sensor. Shading an RF antenna gets more difficult as the frequency goes lower. You could use a complex antenna and phase compare the signals, but I suspect that is beyond your present capabilites.
If you look up robot line follower, the system is similar and will give you some ideas.