Which of the following can be used to enter a transceiver’s operating frequency?
The correct answer is A: The keypad or VFO knob. You can enter a transceiver's operating frequency using the keypad (to directly enter the frequency) or the VFO knob (Variable Frequency Oscillator knob, to tune up and down). These are the primary methods for frequency entry on modern transceivers.
Most modern transceivers have both methods: a keypad for direct frequency entry (you type in 146.520 for example) and a VFO knob for tuning (you rotate the knob to change frequency). Some transceivers also have memory channels you can recall, but the keypad and VFO knob are the fundamental methods for setting frequency. CTCSS/DTMF encoders and AFC are for other functions, not frequency entry.
Exam Tip
Enter frequency = Keypad or VFO knob. Remember: You enter a transceiver's operating frequency using the keypad (direct entry) or VFO knob (tuning). These are the standard methods.
Memory Aid
"**E**nter **F**requency = **K**eypad or **V**FO (think 'EF = KV' = Keypad or VFO)"
Real-World Application
You want to tune to 146.52 MHz. You can either use the keypad to directly enter '146.52' and press enter, or you can use the VFO knob to tune up or down from your current frequency until you reach 146.52 MHz. Both methods work - the keypad is faster for known frequencies, the VFO knob is convenient for scanning or fine-tuning.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. CTCSS and DTMF encoders are for tone signaling and repeater control, not for entering operating frequency.
Option C: Incorrect. Automatic Frequency Control (AFC) automatically adjusts receive frequency to track signals, but it doesn't let you enter a frequency - it follows signals automatically.
Option D: Incorrect. Not all options are correct. Only the keypad and VFO knob are used for frequency entry.
题目解析
The correct answer is A: The keypad or VFO knob. You can enter a transceiver's operating frequency using the keypad (to directly enter the frequency) or the VFO knob (Variable Frequency Oscillator knob, to tune up and down). These are the primary methods for frequency entry on modern transceivers. Most modern transceivers have both methods: a keypad for direct frequency entry (you type in 146.520 for example) and a VFO knob for tuning (you rotate the knob to change frequency). Some transceivers also have memory channels you can recall, but the keypad and VFO knob are the fundamental methods for setting frequency. CTCSS/DTMF encoders and AFC are for other functions, not frequency entry.
考试技巧
Enter frequency = Keypad or VFO knob. Remember: You enter a transceiver's operating frequency using the keypad (direct entry) or VFO knob (tuning). These are the standard methods.
记忆口诀
**E**nter **F**requency = **K**eypad or **V**FO (think 'EF = KV' = Keypad or VFO)
实际应用示例
You want to tune to 146.52 MHz. You can either use the keypad to directly enter '146.52' and press enter, or you can use the VFO knob to tune up or down from your current frequency until you reach 146.52 MHz. Both methods work - the keypad is faster for known frequencies, the VFO knob is convenient for scanning or fine-tuning.
错误选项分析
Option B: Incorrect. CTCSS and DTMF encoders are for tone signaling and repeater control, not for entering operating frequency. Option C: Incorrect. Automatic Frequency Control (AFC) automatically adjusts receive frequency to track signals, but it doesn't let you enter a frequency - it follows signals automatically. Option D: Incorrect. Not all options are correct. Only the keypad and VFO knob are used for frequency entry.
知识点
Frequency entry, Keypad, VFO knob, Transceiver controls
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.