🔍 Key Concepts

• GMDSS distress alerting uses specific digital selective calling (DSC) channels and not voice channels for the initial alert • The dedicated VHF DSC distress channel is different from the VHF radiotelephone distress and calling channel (Ch-16) • Know what EPIRB stands for and which satellite frequency band (in MHz) is internationally allocated for Cospas-Sarsat distress alerts

💭 Think About

• Which option clearly separates DSC alerting channels/frequencies from voice/telex follow‑on channels? Look for the one that focuses on alerting, not follow‑up communications. • Identify the normal VHF voice distress channel (used for MAYDAY by voice) and check whether any option is incorrectly using that channel as a DSC alert channel. • Recall the standard EPIRB distress frequency used by the Cospas‑Sarsat system (in the 400 MHz band). Which option states that correctly and pairs it with DSC distress channels?

✅ Before You Answer

• Verify which VHF channel is the digital selective calling (DSC) distress and safety calling channel (by channel number). • Confirm that EPIRB distress alerts are transmitted on 406 MHz and via the Cospas‑Sarsat satellite system, not on a voice channel. • Check that the correct answer should list only distress alerting allocations (DSC and EPIRB/satellite) and not merely voice ‘Mayday’ channels or generic follow‑on working frequencies.