Jupiter for example emits radio waves from about 10 kHz up to about 300 GHz. This emission is broken into several groupings. The lowest being the kilometric emission which ranges from 10kHz up to 1000kHz. It is the decametric emissions that we are concerned about with Radio Jove. The Radio Jove receiver is tuned to a frequency of 20.1MHz.
Radio waves produced on Earth are mostly manmade and are often at one specific frequency.
In fact, this is one way astronomers can tell a signal created on Earth apart from an astronomical signal. If they are able to tune their receivers to a slightly higher or lower frequency and the signal disappears it is most likely an Earth based signal. Shipping, Aircraft, World Broadcast Communications, Radio Amateurs. Use involves reflecting the signal off the ionosphere back down to waiting recieving stations. Prone to atmospheric changes causing fading and noise.