Although using RG-6 might extend the range of your RP1, I think that the use of RG58 would be more appropriate. I haven't found the specs but for my experience, I'm 99% positive that the antenna impedance for the RP1 is 50 Ohms. Even when the use of RG6 might increase your range the impedance mismatch between the antenna and the cable and then between the cable and the base would cause a signal loss compare to the same setup with a 50 Ohms cable.