Free GMDSS Radio Operator Questions and Answers

Question 1

What radio circuit samples analog signals, records and processes them as numbers, and then converts them back to analog signals?

Accepted Answer

The digital signal processing circuit.

Answer

Explanation:
The digital signal processing circuit in radio communication samples analog signals converts them into digital format for processing as numbers using algorithms, and then converts them back to analog signals. This process improves the efficiency and reliability of communication in the Global Maritime Distress and Safety System (GMDSS).

Question 2

Which of the following statements about SSB voice transmissions is correct?

Accepted Answer

They normally use J3E emissions, which consist of one sideband and a suppressed carrier.

Answer

Explanation:
Single Sideband (SSB) voice transmissions typically use J3E emissions, where only one sideband is transmitted along with a suppressed carrier. This method is efficient in terms of power usage and bandwidth while still providing clear voice communication in radio transmission.

Question 3

How does the COSPAS-SARSAT satellite system determine the position of a ship in distress?

Accepted Answer

By measuring the Doppler shift of the 406 MHz signal taken at several different points in its orbit.

Answer

Explanation:
The COSPAS-SARSAT satellite system determines the position of a ship in distress by measuring the Doppler shift of the 406 MHz distress signal transmitted by an Emergency Position Indicating Radio Beacon (EPIRB). This Doppler shift is measured by multiple satellites as they pass over the distress beacon. By analyzing the Doppler shifts from different satellites and comparing them, the system can triangulate the position of the distress beacon and determine the location of the ship in distress.

Question 4

Which of the following contains a multirange AF voltmeter calibrated in dB and a sharp, internal 1000 Hz bandstop filter, both used in conjunction with each other to perform quieting tests?

Accepted Answer

SINAD meter

Answer

Explanation:
A SINAD (Signal-to-Noise and Distortion) meter is used to measure the quality of a received signal, particularly in radio communication systems. It contains a multirange AF (audio frequency) voltmeter calibrated in decibels (dB) and a sharp, internal 1000 Hz bandstop filter. These components are used together to perform quieting tests, which assess the level of unwanted noise and distortion in a received signal.

Question 5

When sending a DSC call:

Accepted Answer

Vessel's position will automatically be sent if the vessel is sending a "Distress Hot Key" alert.

Answer

Explanation:
When sending a Digital Selective Calling (DSC) distress alert using the "Distress Hot Key" function, the vessel's position will be automatically included in the distress message. However, for routine DSC calls or other types of DSC alerts, the vessel's position is not automatically sent unless manually included in the message by the operator. Therefore, option B is the most accurate statement regarding the automatic transmission of a vessel's position during a DSC call.

GMDSS - Global Maritime Distress and Safety System Practice Test

GMDSS - Global Maritime Distress and Safety System Practice Test

Free GMDSS Radio Operator Questions and Answers