Practice Test Geeks(GROL) General Radiotelephone Operator License Practice Test
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Marine Electronics and Radar Systems Flashcards

7 cards from real GROL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Marine Electronics and Radar Systems flashcards as text

  1. What is the primary frequency band used by marine radar systems?

    Answer: X-band (9–10 GHz)

    Marine radar primarily operates in the X-band (around 9–10 GHz) because this frequency provides good target resolution and is reflected well by water surfaces and vessels.

  2. What does ARPA stand for in marine radar terminology?

    Answer: Automatic Radar Plotting Aid

    ARPA stands for Automatic Radar Plotting Aid, a system that tracks targets and calculates their course, speed, and closest point of approach (CPA).

  3. Which type of radar display shows the ship's own position at the center with north always pointing up?

    Answer: True motion display

    A true motion display moves the own-ship symbol across the screen to reflect actual movement, with north fixed at the top and sea clutter stationary.

  4. What is the purpose of the sea clutter (STC) control on a marine radar?

    Answer: To reduce echoes caused by wave returns close to the ship

    The Sensitivity Time Control (STC) reduces the gain of the receiver for close-range returns, suppressing strong echoes from nearby sea waves that would otherwise obscure targets.

  5. What is the typical pulse repetition frequency (PRF) for a short-range marine radar setting?

    Answer: 1,500–4,000 Hz

    Short-range marine radar settings use higher PRFs, typically 1,500–4,000 pulses per second, allowing more frequent updates at short ranges while keeping pulse width narrow.

  6. What is the function of the magnetron in a conventional marine radar transmitter?

    Answer: To generate the high-power microwave pulses

    The magnetron is a high-power vacuum tube oscillator that generates the microwave frequency pulses transmitted by the radar antenna.

  7. In marine radar, what does 'minimum range' refer to?

    Answer: The closest distance at which the radar can detect a target

    Minimum range is the closest distance a radar can detect a target, determined mainly by the pulse width—longer pulses have greater minimum ranges because the transmitter must stop transmitting before echoes can be received.