🔍 Key Concepts

• HF SITOR (NBDP) is used both for one-way broadcasts and two-way traffic • Maritime Safety Information (MSI) from high seas shore stations is a one‑way broadcast to many ships at once • Different SITOR modes: FEC (Forward Error Correction) vs ARQ (Automatic Repeat reQuest)

💭 Think About

• Is MSI from a high seas shore station meant for a single ship or for all ships in the area at the same time? • Which SITOR mode is designed so that the receiver does not have to transmit back any acknowledgments? • Between the listed choices, which involve broadcast reception rather than a two‑way link?

✅ Before You Answer

• Verify which SITOR mode is specifically associated with one‑way broadcast of safety information • Eliminate options that require a return (acknowledgment) transmission from the ship • Confirm that the selected mode is actually a digital HF SITOR/NBDP mode, not just a general modulation type like AM