Quote Originally Posted by kb2vxa View Post
"i know it's not optimal..."
What's not optimal about it? There is no industry standard, this is AMATEUR radio meaning if it works, use it, don't ask why or how, who cares?
"...but can I use what's already there?"
Bingo, we'll make a ham out of you yet.

OK, let's look at this logically, cheap is good and free is best, right? What you need is already there, free! Sat dish mount used for J-pole, coax used for J-pole, free so far and a couple of connector adapters, cheap. OK, so it's 75 ohms? That means only 1.5:1 SWR feeding a 50 ohm load but a J-pole can match to 75 ohms, the rig may not be 50 ohms exact so expect a fairly good match. Signal loss? The dish's block converter output is in the 800-900MHz region so they use a reasonably low loss coax to feed the receiver on the down side so frankly I wouldn't replace good coax that's already right where you want it.

Oh and BTW toss all that scribble scrabble above out and KISS, keep it simple stupid.
I agree with the above. I would just check to see what kind of cable is there already, and see what max power on it is.