5W is enough?

I made a radio station,the way of modulation is FSK,I want to send the message far to 5Km,so i need a power amplifer,5 Watt is enough?

May anybody recommend me a Schimatic about a 5Watt's power amplifer?

Thanks~~~~~

5W is too much if you use low frequency as 100MHz..
Look space attenuation curves at the frequency which you would use and then calculate the power that you'll need by counting "sensivitiy" of the receiver by adding at least 12-15 dB S/N margin...

But at first sight ( I preassume you'll use low RF frequencies) 5W is toomuch..

You should tell whatthe sensitivity of the receiver and the efficiency of the antenna are!
then we can give you some advice about the PA.