Abstract: Radio over Free Space Optics (Ro-FSO) is promising future communication techniques. In this study, design Ro-FSO with mathematical analysis for transmission and simulation comparison of radio frequency RF (20, 60) GHz for transporting 2.5 and 10 Gbps over acceptable maximum distance are possible of FSO under clear air, light rain, moderate rain and heavy rain weather condition. To knowing the ability radio frequencies for carrying difference values of information (data rate) over the same optical source 1550 nm.