How does VHF communication work in aviation?

VHF (Very High Frequency) communication uses frequencies from 118.000-136.975 MHz for voice communication between aircraft and ground stations (ATC, airlines). Characteristics include: Line-of-sight propagation (limited by curvature of Earth, range depends on altitude), Amplitude modulation (AM) for analog voice (legacy), and Digital voice (VDL) for modern applications. Range is approximately 200 nm at cruise altitude. VHF is the primary communication means in continental airspace. Aircraft carry multiple VHF radios for redundancy. Frequency congestion in busy airspace is addressed through 8.33 kHz channel spacing in Europe.