RYA SRC DSC Operations — Questions and Answers
Question 1: What does 'DSC' stand for in marine radio communications?
- Direct Safety Communication
- Digital Selective Calling (Correct answer)
- Distress Signal Channel
- Digital Ship Control
Correct answer: Digital Selective Calling
DSC stands for Digital Selective Calling. It is a digitally encoded signalling system that allows radio operators to send automated alerts and calls to specific stations or all stations.
Question 2: On which VHF channel are DSC calls transmitted?
- Channel 16
- Channel 70 (Correct answer)
- Channel 6
- Channel 13
Correct answer: Channel 70
All VHF DSC calls are transmitted and received on Channel 70 (156.525 MHz). This channel is dedicated exclusively to DSC traffic and should never be used for voice communications.
Question 3: What is an MMSI number and why is it important for DSC?
- A type of radio antenna
- A unique nine-digit Maritime Mobile Service Identity that identifies a specific vessel or coast station in the DSC system (Correct answer)
- A weather code
- A frequency designation
Correct answer: A unique nine-digit Maritime Mobile Service Identity that identifies a specific vessel or coast station in the DSC system
An MMSI (Maritime Mobile Service Identity) is a unique 9-digit number assigned to each DSC-equipped vessel or coast station. It acts like a telephone number, allowing specific calls to be made.
Question 4: What happens when you press the dedicated 'DISTRESS' button on a DSC VHF radio?
- It turns the radio off
- It sends an automated distress alert on Channel 70 containing your MMSI, position, and nature of distress to all DSC-equipped stations (Correct answer)
- It calls the police
- It switches to Channel 16 only
Correct answer: It sends an automated distress alert on Channel 70 containing your MMSI, position, and nature of distress to all DSC-equipped stations
Pressing and holding the distress button transmits a DSC distress alert on Channel 70 to all stations. The alert includes your MMSI, position (from GPS), time, and nature of distress if programmed.
Question 5: After sending a DSC distress alert, what should the operator do next?
- Switch the radio off
- Switch to Channel 16 and broadcast a Mayday voice message to provide full details of the distress (Correct answer)
- Wait for an email response
- Make a phone call to the marina
Correct answer: Switch to Channel 16 and broadcast a Mayday voice message to provide full details of the distress
After the DSC alert on Ch70, the radio should switch to Channel 16 where the operator must make a full Mayday voice call providing complete details including position, nature of distress, and assistance required.
Question 6: How should a DSC distress alert be cancelled if it was sent accidentally?
- There is no way to cancel it
- Cancel the alert on the radio, then broadcast a cancellation message on Channel 16 to all stations and inform the coastguard (Correct answer)
- Simply switch the radio off
- Send another DSC call saying 'cancel'
Correct answer: Cancel the alert on the radio, then broadcast a cancellation message on Channel 16 to all stations and inform the coastguard
If a false distress alert is sent, the operator must cancel it on the radio, then broadcast a cancellation on Channel 16 to all stations explaining it was a false alert, and contact the coastguard.
RYA SRC DSC Operations
What does 'DSC' stand for in marine radio communications?