What kind of coax, what frequency, what kind of antenna, and so on and so 
on.  Makes a big difference.  If you're talking 2m or above, I'd have to 
check the tables, but it is quite a loss.  You want to at least run 
something like lmr 400 or similar.  With rg8, even on two, a couple 
hundred feet is a lot of loss.  Of corse, hard line is best, but very 
expensive these days.
What I'm saying is we need more details.
73s
Butch Bussen
wa0vjr