🔍 Key Concepts

• VHF (Very High Frequency) vs HF (High Frequency) radio bands and their typical uses • How time of day (mid-day vs night) affects radio wave propagation, especially for HF • The normal range and purpose of marine VHF (156–174 MHz) for ship-to-ship and ship-to-shore

💭 Think About

• Which radio bands listed are normally used for marine VHF communications with nearby shore stations? • How does skywave/ionospheric reflection affect HF frequencies (like 12 and 22 MHz) compared with higher VHF frequencies over a relatively short distance like 15 miles? • For a 15‑mile distance in daylight, do you primarily rely on line-of-sight or on long-distance skip propagation?

✅ Before You Answer

• Identify which option corresponds to the standard marine VHF band (Channel 16, working channels, etc.) • Check typical service range of marine VHF for a vessel to a shore station and compare it to 15 miles • Confirm which bands (in MHz) are more suitable for long-range HF skywave communication rather than short-range coastal communication