Explanation: 2182 kHz and VHF Channel 16 are designated international distress, urgency, and safety calling frequencies. These channels are critical for maritime safety and must remain clear for actual emergency communications. Transmitting test signals on these frequencies creates a signal that could be mistaken for a distress call or interfere with legitimate emergency traffic. To prevent false alarms and ensure these vital channels are available when needed, regulations strictly limit the duration of test transmissions. A 10-second limit within any 5-minute period allows for a brief functionality check of the equipment without causing significant interference or confusion. Longer transmission times, such as 30 seconds, 1 minute, or 2 minutes, would pose a much higher risk of interfering with actual distress communications or generating a widespread false distress alert.