VHF Radio Procedures Flashcards

What is VHF Channel 70 exclusively reserved for?

Answer: Digital Selective Calling (DSC)

Channel 70 is exclusively reserved for Digital Selective Calling (DSC) and must not be used for voice communications.

After transmitting a DSC distress alert on Channel 70, on which channel should the subsequent voice MAYDAY call be made?

Answer: Channel 16

Following a DSC alert on Ch 70, the voice MAYDAY and all distress communications take place on Channel 16.

What is the maximum transmit power of a handheld VHF radio?

Answer: 5 watts

Handheld VHF radios have a maximum output of 5 watts, compared to 25 watts for fixed-mount units.

When changing from Channel 16 to a working channel, what is the correct procedure?

Answer: Acknowledge on Ch 16, confirm the working channel, then both vessels switch

Both parties should confirm the agreed working channel on Ch 16 before switching, ensuring no miscommunication.

Which international body is responsible for allocating VHF marine radio channels?

Answer: ITU (International Telecommunication Union)

The ITU allocates and regulates the use of the radio frequency spectrum, including marine VHF channels, internationally.

Which VHF channel is designated as the UK Small Craft Safety channel, commonly used for communications with HM Coastguard by small vessels?

Answer: Channel 67

Channel 67 is the UK Small Craft Safety working channel, used by HM Coastguard to communicate with small craft after initial contact on Ch 16.

When is it appropriate to use high power (25 watts) rather than low power (1 watt) on VHF?

Answer: When low power is insufficient to establish or maintain communication

Low power (1W) should be used for short-range communications; high power (25W) is used when low power cannot achieve the required contact.