🔍 Key Concepts
• Meaning of common ARQ (Automatic Repeat reQuest) prosigns such as OBS+, WRU, GA+?, BRK+, KKKK in ITU/USCG radio procedures
• How ARQ codes indicate: 1) type of traffic (e.g., synoptic weather), 2) transfer of control between stations, 3) termination of a phase with a coast station
• Difference between codes used to request identification/control and those used to end/terminate a link or phase
💭 Think About
• Which ARQ prosign is normally used to request or send synoptic weather observations in ship–shore traffic? Identify that first, then see which options start with it.
• Which code in the options indicates "go ahead" or transfer of control from one station to another, and which code indicates that a phase or link with the coast station is being terminated?
• Look at the middle codes in each option: which one correctly represents a change of control from transmitting station to receiving station, rather than simply calling, identifying, or ending traffic?
✅ Before You Answer
• Confirm from your radio procedures reference which ARQ code is explicitly associated with synoptic weather transmissions.
• Verify which symbol (e.g., GA+?, +?, WRU, Here is) corresponds to requesting the other station to transmit / passing control in ARQ operation.
• Check which prosign (BRK+ vs KKKK) is used to end phasing with a coast station rather than to end the entire communication link.