TWO portable Dish antennas for two-channel access?

I have a question. about the portable Dish antennas - I am located in Montana, in a Park where I've stayed for years. Great parking spot in the park - but - the trees have grown up such that, when it's windy, the signal goes in and out from my roof antenna (Traveler). I have a 722 Dish DVR with the two inputs, connected as usual with the roof, via a splitter and the single input coming in from the rooftop.
My question is whether I could buy TWO portables, plug TWO coaxials from the two...

TWO portable Dish antennas for two-channel access?