🔍 Key Concepts
• MF (Medium Frequency) band used for maritime distress and safety communications
• DSC (Digital Selective Calling) distress, urgency, and safety alerting on MF
• Difference between a specific DSC distress frequency and other MF DSC calling/safety frequencies
💭 Think About
• List the DSC frequencies you know in the MF band and decide which of them are specifically authorized for distress-related calls (distress alert, distress acknowledgement, distress relay, distress traffic, urgency/safety related to distress).
• Think about how GMDSS divides DSC distress working on MF versus HF and VHF. Which MF DSC channels are used when a ship sends an initial distress alert and when shore stations respond?
• Ask yourself if all MF DSC calling/safety frequencies are used for distress purposes, or if some are only for routine/traffic calls.
✅ Before You Answer
• Verify from a GMDSS frequency table which MF DSC frequencies are marked specifically as distress and safety or distress, urgency, safety and calling.
• Confirm that you are only counting MF DSC frequencies (not the associated radiotelephony distress frequencies like 2182 kHz).
• Double‑check that you are not accidentally including HF DSC distress frequencies (in the 4, 6, 8, 12, 16 MHz bands) in your count—MF is a separate band.