Need to think about charge displacement and fields rather than electrons. The electrons moving in wire (direct current) circuit only move, on average, a few cm

Need to think about charge displacement and fields rather than electrons. The electrons moving in wire (direct current) circuit only move, on average, a few cm/sec. Now the charge displacement moves at the speed of light. Think of a tube stuffed tightly with marbles. Push the marbles at one end, and they move near instantly at the other end. The force transfers instantly, but the marbles may hardly move. Now imagine the marbles connected with stiff, little springs. Push on one end, and the compression wave moves through the charges quickly (the speed depends on the spring constant). It hits the other end, yielding a little more charge accumulation, then bounces back, yielding a little less charge. Do that a 2.5 billion times a second and you have a WiFi antenna. The charges don’t move much all; it’s the charge displacement that moves, which is the E and H field. The key is also that the displacement must have acceleration (harmonic motion) to have a derivative. Accelerating charges radiate; constant velocity charges (direct current) don’t. The jist of it is that all the energy is contained in the fields. That metal rod has charge that is easily displaced. Now as to how an accelerating charge radiates; I can’t remember, but Feynman covers it in his 3 volume lectures.