🔍 Key Concepts

• NAVTEX (Navigational Telex) is a medium‑frequency (MF) narrow‑band direct‑printing service used for MSI (Maritime Safety Information) • Typical MF ground-wave propagation ranges over seawater • The intended coastal coverage of NAVTEX within the Global Maritime Distress and Safety System (GMDSS)

💭 Think About

• Think about what role NAVTEX plays in GMDSS: is it meant for close‑in coastal waters, ocean‑wide coverage, or only harbor approach? • How far can an MF ground wave normally travel over the sea before signal strength becomes too weak for reliable reception? • Compare the options: which ranges sound more like HF (long-range) vs VHF (line‑of‑sight) vs MF (regional/coastal)?

✅ Before You Answer

• Match the range with coastal coverage, not ocean‑wide or purely harbor‑limited coverage • Eliminate any answer that clearly describes line‑of‑sight VHF behavior or oceanic HF behavior rather than MF ground‑wave • Recall that GMDSS divides sea areas (A1, A2, A3, A4); NAVTEX is primarily for A1/A2 coastal coverage, so pick a range consistent with that