QAM
Quadrature Amplitude Modulation. This is an efficient way of transferring binary data over cable. It is used for multiple dwelling unit installations. They set up a few LNB dishes and send the output to a QAM converter rack. Then they send the signals into the cable entering the apartment building. The people wanting to receive these signals connect their satellite receiver to the cable and they can then receive satellite TV. The downfalls are that mostly everyone working for the satellite company knows nothing about it. Also, misalignment of a dish will affect everyone and you probably don't have direct access to re-align that dish.

QPSK
The type of modulation DirecTV uses in their satellite transmissions.