🔍 Key Concepts

• HF vs VHF frequency bands and where 22 MHz actually falls • How ITU HF marine channel numbers (e.g., 4xxx, 6xxx, 8xxx, 12xxx, 16xxx, 18xxx, 22xxx) correspond to specific MHz bands • The special purpose of DSC-only channels and whether they relate to 22 MHz

💭 Think About

• First, decide whether 22 MHz is in the HF band or the VHF band; which options are clearly VHF-only? • Look at the numbering pattern of the channels listed. Which one matches the typical numbering used for HF 22 MHz ITU channels? • Consider what Ch-22A and Ch-70 are normally used for in everyday marine VHF operations—do either of those usages sound like a 22 MHz HF service?

✅ Before You Answer

• Confirm that VHF marine channels are around 156–162 MHz, not 22 MHz • Recall that HF marine ITU channels in the 22 MHz band usually have channel numbers starting with 22xx • Verify that DSC Ch-70 is a dedicated VHF DSC distress/safety calling channel, not an HF 22 MHz channel