How can you avoid harmful interference on an apparently clear frequency before calling CQ on CW or phone?
The correct answer is A: Send 'QRL?' on CW, followed by your call sign; or, if using phone, ask if the frequency is in use, followed by your call sign. To avoid harmful interference on an apparently clear frequency before calling CQ, you should send 'QRL?' on CW or ask if the frequency is in use on phone, followed by your call sign. This checks if the frequency is actually clear before you start calling. For amateur radio operators, this is good operating practice that prevents interference. Understanding this helps ensure proper frequency selection.
Exam Tip
Check frequency before CQ = send 'QRL?' (CW) or ask if in use (phone), then your call. Think 'Q'RL? = 'Q'uery if 'R'adio 'L'ine is busy. Check if frequency is clear before calling CQ. Not just listening, not 'test', not 'QSY'.
Memory Aid
"Check frequency before CQ = 'QRL?' (CW) or ask if in use (phone), then call. Think 'Q'RL? = 'Q'uery if 'R'adio 'L'ine is busy. Standard procedure to check if frequency is clear before calling CQ."
Real-World Application
You want to call CQ on 20 meters. Before calling, you send 'QRL? DE K2XYZ' on CW, or say 'Is this frequency in use? This is K2XYZ' on phone. This checks if anyone is using the frequency. If no response, it's clear to call CQ. This prevents interfering with stations you might not hear.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Listening for 2 minutes might help but isn't the recommended method - actively asking 'QRL?' or 'is this frequency in use?' is better.
Option C: Incorrect. Sending 'V' or saying 'test' isn't the standard method - 'QRL?' or asking if frequency is in use is the proper procedure.
Option D: Incorrect. Sending 'QSY' means 'change frequency' - that's not what you want. You want to check if the frequency is clear, not tell others to change.
题目解析
The correct answer is A: Send 'QRL?' on CW, followed by your call sign; or, if using phone, ask if the frequency is in use, followed by your call sign. To avoid harmful interference on an apparently clear frequency before calling CQ, you should send 'QRL?' on CW or ask if the frequency is in use on phone, followed by your call sign. This checks if the frequency is actually clear before you start calling. For amateur radio operators, this is good operating practice that prevents interference. Understanding this helps ensure proper frequency selection.
考试技巧
Check frequency before CQ = send 'QRL?' (CW) or ask if in use (phone), then your call. Think 'Q'RL? = 'Q'uery if 'R'adio 'L'ine is busy. Check if frequency is clear before calling CQ. Not just listening, not 'test', not 'QSY'.
记忆口诀
Check frequency before CQ = 'QRL?' (CW) or ask if in use (phone), then call. Think 'Q'RL? = 'Q'uery if 'R'adio 'L'ine is busy. Standard procedure to check if frequency is clear before calling CQ.
实际应用示例
You want to call CQ on 20 meters. Before calling, you send 'QRL? DE K2XYZ' on CW, or say 'Is this frequency in use? This is K2XYZ' on phone. This checks if anyone is using the frequency. If no response, it's clear to call CQ. This prevents interfering with stations you might not hear.
错误选项分析
Option B: Incorrect. Listening for 2 minutes might help but isn't the recommended method - actively asking 'QRL?' or 'is this frequency in use?' is better. Option C: Incorrect. Sending 'V' or saying 'test' isn't the standard method - 'QRL?' or asking if frequency is in use is the proper procedure. Option D: Incorrect. Sending 'QSY' means 'change frequency' - that's not what you want. You want to check if the frequency is clear, not tell others to change.
知识点
Frequency checking, QRL?, Operating procedures, Good operating practice
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.