Let's take a look at the basics of Radio Frequencies: 2.4 GHz and 5.8 GHz are two of the most common frequencies when you are dealing with FPV Quadcopter drones. 2.4 GHz is the common RF used by Quadcopters for connecting the ground transmitter to the drone.
So the frequency of the common uav jammer is 2.4GHz. It's also a common frequency for WIFI.