The FM radio band is around 100MHz.
So lets say for sake of argument that it is legal to jam radio frequencies on your own property, which it's not, state laws are superseded in these situations. For instance you can be arrested by a DEA agent in California for smoking marijuana even though is it legal there. How are you gonna keep the jamming to just your property? I'm gonna go ahead and say it would be very difficult to do if not impossible.
That being said if you wanna brake the law that's your prerogative. By definition a radio jammer decreases the signal to noise ratio of a given broadcast. You do this by increasing the noise as you have no control over the signal. So you need a way to create noise and a way to transmit that noise.