🔍 Key Concepts

• NAVTEX message header structure (what pieces of information appear first and how they are coded) • Difference between station identification, subject/category identification, and message numbering in NAVTEX • How letters and numbers are used differently in NAVTEX coding

💭 Think About

• Ask yourself: In NAVTEX, which part (station, subject, or message number) is represented by a single letter from A–Z? • Consider how many categories of messages (navigational warnings, meteorological warnings, SAR, etc.) there are—would that be better coded by a letter or by a two‑digit number? • Think about whether the date/time group is actually part of the short NAVTEX header line or if it appears elsewhere in the message format

✅ Before You Answer

• Verify from your GMDSS/NAVTEX reference what the B1, B2, and B3B4 characters in the header represent. • Check whether the message category is identified by a letter or a number in the official NAVTEX specification. • Confirm if the standard NAVTEX header line explicitly includes a date/time group, or if date/time is handled differently.