I am also a ham operator (Amateur Radio). Radio waves do travel in the line of sight. I have talked to the ISS three times from my home. It is easy but only when it passes overhead. And yes the distance I can use my VHF radio on the earth will be about 60 miles. If the earth would be flat I could communicate thousands of miles but because of the curvature of the earth, I can't.
Is there any ham operated that believe the earth is flat?