I support BB. But there is more
FIrst, since you are using SAT TV you should have been using good RG-6 all along, Oh the RV makers say "RG_59 won't matter for that short run) but on the average RG-58 has FOUR TIMES the loss of RG-6.. And if you go to lowest bidder.. That goes UP.
So I would replace all coax antenna to Receiver with a SINGLE run of RG-6
Next. Antenna placement is critical.. The antenna MUST have a clear view of the Sat.. if there is a tree in the way. or your RV, or a building, or a power iine.. Moving it a few feet can make a BIG difference.