OK i no the coax im using is a load of crap and im thinking of replacing it

but is it really nessesary i have 90% signal and 70-75% quality for 28.8 and 28.5, the coax is RG6u, i know its crap because i have 50ohm rg6 for my old cb setup and its superior to 75ohm stuff.
So replacing it , will it improved any thing