Ok, so as I understand, to move the S meter of the receiving end, you must multiply the power times 4. But my question is, at what point do you start using this formula? Let's say for example if I have a 4 watt radio, if this holds true, then I would have to boost my power output to 16 watts for 1 S unit, correct? And if I wanted to boost my receivers end to 2 units, I would have to boost my power to 64 watts (14X4), and for 3 S units, to 256 watts (64X4).... Am I thinking of this correctly??? Now let's say I have a 100 watt radio. If my thinking is correct, to move the other party's S meter an S unit, I would need to step power output to 400 watts? And another S unit, 1600 watts? (of course not legal at this rate). I've also "heard" that "the first 100 watts is what matters". Is that why many HF radios have a 100 watt max output? Thoughts? Thanks in advance.