Plenum is the spec that says if your house is on fire, the cable doesn't give off deadly fumes when it burns. Not sure what "riser" means.
Can it be used for satellite?
Easy answer: No. Not-so-easy-answer: Depends.
If there are ANY splitters in the line, buried inside a wall or hidden somewhere for example, it will not work period.
If it's RG-59 and not RG-6 it might or might not work, depending on total distance to the dish and other factors such as age and quality of the cable which is unknown. You might get by with such a cable basically getting from the outside of the house to where your receiver is, and make sure to use good quality RG-6 for the rest of it.
Bottom line, there's no way to know for sure without just trying it.
Plenum cable is rated for commercial use where the ceiling is a drop type and the entire area above it is used for air return (without return ductwork). If the cieling has return ductwork then a standard cable can be used. The code CMP will appear on the side of the cable. If it has CATV then it's a good chance it's RG6. BTW, if it does have CMP on it, DO NOT GIVE IT AWAY - that stuff is real pricey.
Well it will proably work,just check to see if there are any splitters in the line and if not hook it up and see what you get. Also if you have a wire that you know for sure is RG-6 look at the whole in the end of the fitting a RG-59 fitting and compair the two, RG-59 has a slightly smaller hole than the RG-6. good luck hope this helps...