OK, so I had this thought while looking for a mobile dual-band radio: Why or when would you ever need more than a few watts of output power? For example, the FM satellites have less than 1 watt, with omnidirectional antennas, and we can pick up their signal over several hundred km with cheap HTs, sometimes with even just a rubber duck antenna. So in what cases would more than a few watts of power be needed for communications on earth? Simplex is usually no more than 10-20 km, repeaters about 70-100 at max. What are the factors that affect how much power we need to get through?