🔍 Key Concepts
• Propagation characteristics of HF, MF, and satellite communications
• How atmospheric disturbances (ionospheric noise, static, thunderstorms, solar activity) affect radio waves
• Which services use terrestrial radio vs satellite links
💭 Think About
• Identify which options use HF or MF radio and which, if any, rely primarily on satellites
• Think about which frequencies are most affected by ionospheric conditions, thunderstorms, and static: HF, MF, or satellite bands?
• Consider which service is specifically designed to maintain reliability even when there is heavy static and atmospheric noise at sea
✅ Before You Answer
• For each choice, note its frequency band (HF, MF, or satellite)
• Recall that HF and MF are both forms of terrestrial radio that can be strongly affected by atmospheric/ionospheric conditions
• Identify the option that depends on a space-based system rather than propagation through the lower atmosphere