ROC AGC, Power, Emissions, Propagation & Sea Area Quiz
1. What is the purpose of Automatic Gain Control (AGC) in a GMDSS radio?
To adjust the gain of the received signal automatically.
To increase the transmission power of the signal.
To reduce the noise in the transmitted signal.
To automatically change the frequency of the signal.
2. How is the emission power of a radio transmitter controlled in GMDSS?
By adjusting the transmitter power output manually.
By using an automatic power control (APC) system.
By controlling the antenna direction.
By adjusting the frequency of the transmission.
3. What is the legal maximum emission power for a GMDSS radio?
25 watts.
50 watts.
100 watts.
150 watts.
4. What is the primary mode of propagation for VHF radio signals?
Line of sight propagation.
Skywave propagation.
Groundwave propagation.
Space wave propagation.
5. How does radio propagation differ between low and high frequencies?
Low frequencies travel further and are less affected by the atmosphere.
High frequencies travel further and are less affected by the atmosphere.
High frequencies are absorbed more by the ionosphere.
Low frequencies are more easily absorbed by the ionosphere.
6. What causes radio waves to refract or bend?
Changes in temperature or humidity in the atmosphere.
A change in the frequency of the wave.
The size of the antenna.
The power of the transmitter.
7. What is skywave propagation typically used for?
Long-distance communication via ionospheric reflection.
Short-range communication.
Surface communication over a landmass.
Communication between satellites.
8. What is the effect of frequency on radio wave propagation?
Lower frequencies travel further but are slower.
Higher frequencies travel further and faster.
Higher frequencies are absorbed by the ionosphere.
Lower frequencies are absorbed by the ionosphere.
9. Which GMDSS sea area does the HF DSC system cover?
Sea Area A1.
Sea Area A2.
Sea Area A3.
Sea Area A4.
10. What is the minimum requirement for a Sea Area A1 vessel?
VHF radio with DSC.
Satellite communication system.
HF radio.
Inmarsat C terminal.
11. Which Sea Area requires satellite communication coverage?
Sea Area A1.
Sea Area A2.
Sea Area A3.
Sea Area A4.
12. What is the frequency range for GMDSS in Sea Area A3?
1.6 MHz to 30 MHz.
30 MHz to 300 MHz.
400 MHz to 500 MHz.
1.5 GHz to 1.6 GHz.
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