Radar Observer · Operation — Guard Zone
A guard zone (guard ring) alarm on a radar is used to:
- AAutomatically alter course to avoid targets
- BSound an alert when a target enters a set range/bearing area around own ship✓ Correct
- CIncrease transmitter power
- DPlot the tide
Explanation
A guard zone is an operator-set area; the radar alarms when any new echo enters it. It is an aid to alert the watch — not a substitute for continuous radar observation and a proper lookout.
Authority: Radar Operation (USCG topic)
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