Maximum effective range of RG-6/U in CCTV
Rg6/U is rated up to a max of 1000-1500 feet. 
If you need longer you can use Rg11 which is up to 3000ft.

You'll also need power. (They do make hybrid cable that has RG6/u and 2 x 18 Gauge wires for power.) 

Make sure to ensure that the proper power is supplied on a long run. You can use this calculator.