🔍 Key Concepts

• HF propagation factors relevant to GMDSS: distance, time of day, season, sunspot activity, solar flares • Difference between short‑term operational planning vs. long‑term forecasting of radio conditions • Which factors change hour‑to‑hour, month‑to‑month, and over the 11‑year sunspot cycle

💭 Think About

• Which factor must you think about every time you set up a circuit or choose a frequency for a specific call today? • Which factor changes more slowly over months and years, rather than within a single watch? • Would you normally plan for rare disturbances (like major flares) first, or for the usual, predictable changes that affect every watch?

✅ Before You Answer

• Be clear which factor affects day‑to‑day frequency choice the most. • Rank the factors from most immediate and predictable for daily operations to least frequently used in routine planning. • Check which answer puts distance & time of day in a position that matches how often you actually use them as an operator.