[gamblor956]

I have a handheld walkie-talkie radio from REI that can transmit 10-20 miles from the top of a hill in not-perfect conditions (and about 1-2 miles in forested terrain), so I think your range estimates are off by an order of magnitude for high-powered transmissions.

[vvanders]

Nah, he's pretty on the mark. I'm lucky to make it into the repeater ~15mi down the road from me(50W on both side) because it's not at the top of a mountain. Unless you're talking HF(which he covers) you're basically still constrained by line-of-sight.

More power just pushes you through small objects(trees, buildings, etc) depending on wavelength.