Re: Satellite dish...why some dish perform better than other
Answer: device technology for front-end receivers
I remember in the early 80's commercial satellite TV dishes were half the size of a single family home rooftop, and they had to be accurately aligned to the "bird in the sky" in order to decently receive a signal. In the mid-90's, HEMFET technology took off and a higher signal-to-noise ratio (SNR) could be received at the dish.
One of the major developments in HEMFET technology was the placement of the transistors conducting channel a few hundreds of nanometers below the air-semiconductor interface. The reduction of surface scattering is essentially what allowed for higher SNRs. Therefore, less signal energy needed to be collected and as a result, dishes could be made smaller.
I assume that the same is true today. As device engineers make transistors with higher SNRs, component engineers can make better front-end receivers, and systems engineers can reduce the size of their dishes.