The specifications listed on this page: http://www.classbforum.com/phpBB2/vi...hp?f=11&t=1380
indicate that it has a "Built in TV antenna".
Inside your van, where the TV connects is there some type of signal source switch? Maybe labeled Cable / Air or simply A / B. There might be a signal amplifier there also.
Adding an inverter to your van will let you convert 12 volt DC battery power to the 120 volt AC needed by most TV's and your satellite receiver. A 500 or 750 watt inverter should be more than enough for what you describe. You won't need to run the generator to watch TV then.