How does the VHF/UHF radio horizon compare to the geographic horizon?
Atmospheric refraction bends VHF and UHF signals slightly toward Earth, so the radio horizon is about 15 percent farther than the purely geometric horizon.
Amateur Extra · FCC Element 4 · answer reveals automatically
Atmospheric refraction bends VHF and UHF signals slightly toward Earth, so the radio horizon is about 15 percent farther than the purely geometric horizon.