You need a second receiver to watch/record two shows.
You need a second dish because Echostar divides local channels in many markets, putting some channels on the main satellites at 110/119 and other channels on side satellites way off to the east or west of the main satellites (61.5/148). The satellites are too far apart for a single dish to "see" the different positions. The receiver combines the signals from the two satellite dishes into one seamless group of channels.