🔍 Key Concepts

• VHF radio propagation is mostly "line-of-sight" between antennas • The effect of antenna height and installation quality on range • The difference between ionospheric refraction (skywave) and local, direct-wave communications

💭 Think About

• Which of these factors would change how far a VHF signal can travel over the surface by line-of-sight? • Which option relates to long-distance, HF/shortwave communications rather than typical marine VHF use? • Think about which item would matter even if you were standing on a dock with a handheld VHF talking to a nearby boat.

✅ Before You Answer

• Identify which options clearly change the strength or clarity of the signal reaching the other antenna. • Decide which item is associated with long-range skywave propagation, not normal marine VHF range. • Confirm that marine VHF (around 156–162 MHz) normally uses direct, line-of-sight paths, not bouncing off the ionosphere.