Practice Test Geeks(CMRT) Certified Marine Radar Technician Practice Test
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Installation & Maintenance Procedures Flashcards

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

Read the first 7 Installation & Maintenance Procedures flashcards as text

  1. A radar installation requires a rotary joint between the stationary waveguide and the rotating antenna. The key performance parameter checked for a rotary joint is:

    Answer: Insertion loss and VSWR across rotation

    A rotary joint is verified for consistent insertion loss and acceptable VSWR throughout its full 360° rotation to ensure uniform signal transfer.

  2. During a post-installation performance test, the radar's minimum range is found to be excessive. The most likely cause is:

    Answer: Excessive transmit pulse length or recovery time

    Minimum range is limited by the transmit pulse length and receiver recovery (dead) time; longer pulses or slow recovery blind the receiver at close range.

  3. When installing radar on a vessel with an aluminum superstructure, bonding straps between the antenna mount and the vessel's ground plane should be:

    Answer: Made of copper braid with low impedance

    Low-impedance copper braid bonding straps provide effective RF ground and also reduce galvanic corrosion risk by equalizing potentials.

  4. A technician notices the radar antenna rotation rate has slowed from 24 RPM to 18 RPM. The FIRST component to inspect is:

    Answer: The antenna drive motor and gearbox

    Reduced rotation rate points directly to the antenna drive motor or gearbox — worn gears, low lubricant, or motor winding failure are common causes.

  5. What is the correct procedure when installing a new magnetron to ensure proper break-in?

    Answer: Gradually increase power over several hours per manufacturer schedule

    New magnetrons require a manufacturer-specified conditioning (burn-in) procedure, gradually increasing power to stabilize emission characteristics and extend tube life.

  6. Radar cables passing through below-deck spaces must be routed to avoid proximity to:

    Answer: Engine exhaust lines and high-heat sources

    Heat from exhaust lines degrades cable insulation and connectors, causing intermittent faults and potential fire hazard in radar cable runs.

  7. When performing an ARPA radar commissioning test, which check specifically validates target tracking accuracy?

    Answer: Tracking a target at a known course and speed and comparing to ARPA output

    ARPA accuracy is validated by acquiring a target with a known course and speed (e.g., a buoy or vessel) and confirming the ARPA displayed values match.