Coast Guard Exams
Question 69Deck Safety70% to pass

Which system is least likely to be subject to fading or static interference?

AI Explanation
The correct answer is C) Digital Selective Calling on channel 70. Digital Selective Calling (DSC) on channel 70 is the least likely to be subject to fading or static interference compared to the other options. DSC on channel 70 utilizes a dedicated, interference-free frequency assigned by the International Telecommunications Union (ITU) for distress and safety communications. This frequency is closely monitored and less susceptible to environmental factors that can cause fading or static on other maritime communication systems like HF SITOR, INMARSAT, or VHF ARQ. The other options, such as HF SITOR and INMARSAT, are more vulnerable to interference and fading due to atmospheric conditions and satellite signal propagation challenges. VHF ARQ, while less affected by long-distance propagation issues, can still experience interference from nearby radio transmissions on the same frequency band.

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