Subelement B: MF-HF-DSC-SITOR (NBDP) Equip. & Operations— Topic :
Question 17B5
Element 9 (GMDSS Maintainer)Which of the following conditions would be a symptom of malfunction in a 2182 kHz SSB radiotelephone?
Explanation
When operating an SSB radiotelephone, power output should be observed when speaking into the microphone, as SSB transmitters only produce RF power when modulated by voice (or other audio). If you speak into the microphone and there's no indication of power output, it signifies a failure in the transmitter's audio processing, modulation, RF amplification, or power supply section, indicating a malfunction.
Here's why the other options are incorrect:
* **B) Much higher noise level observed during daytime operation.** 2182 kHz is in the MF (Medium Frequency) band. Atmospheric noise (static from lightning, etc.) can vary significantly due to environmental factors, time of day, and location. Increased noise, even during the daytime, is often a propagation characteristic or an external factor (QRN), not necessarily a malfunction of the radio itself.
* **C) When testing a radiotelephone alarm on 2182 kHz into an artificial antenna, the Distress frequency watch** This option is an incomplete sentence and cannot be evaluated as a correct answer.
* **D) Failure to contact a shore station 600 nautical miles distant during daytime operation.** 2182 kHz relies heavily on groundwave propagation during the day, which has a limited range. Skywave propagation, which allows for longer distances, is significantly attenuated in the MF band during daylight hours due to D-layer absorption. Therefore, failing to contact a station 600 nautical miles away during the day is more likely due to normal propagation limitations rather than a radio malfunction.
Related Questions
17B3 Which would be an indication of proper operation of a SSB transmitter rated at 60 watt PEP output?17B4 An MF-HF transceiver is functioning correctly in voice mode/SSB but not in SITOR (NBDP). What is the most likely source of the problem?17B6 Which would indicate proper operation of a SSB transmitter rated at 60 Watt PEP output in J3E mode?18B1 Which of the following conditions indicate the proper operation of a 150 Watt MF/HF transmitter in the F1B ARQ mode?18B2 Which of the following conditions indicate the proper operation of a 250 Watt MF/HF transmitter in the F1B FEC mode?