Which of the following may cause receive interference to an HF transceiver installed in a vehicle?
The correct answer is D: All these choices are correct. What may cause receive interference to an HF transceiver installed in a vehicle includes: the battery charging system, the fuel delivery system, and the control computers. All three can generate electrical noise that interferes with HF reception. For amateur radio operators, this explains common mobile interference sources. Understanding this helps when troubleshooting mobile interference.
Exam Tip
All three can cause mobile receive interference: battery charging system, fuel delivery system, control computers. When all listed systems can cause interference to mobile HF transceivers, 'all of the above' is usually the answer. All generate electrical noise.
Memory Aid
"All three can cause interference: Battery charging, Fuel delivery, Control computers. Think 'A'll 'V'ehicle 'S'ystems can cause interference. All three generate electrical noise that interferes with HF reception. Common mobile interference sources."
Real-World Application
Your HF mobile transceiver experiences interference. Investigation reveals: (1) Battery charging system (alternator) generates noise, (2) Fuel delivery system (fuel pump, injectors) generates noise, (3) Control computers (ECU, various modules) generate noise. All three systems can cause interference to HF reception.
Key Concepts
Why Other Options Are Wrong
Option A: While correct, this is incomplete. Fuel delivery system and control computers also cause interference.
Option B: While correct, this is incomplete. Battery charging system and control computers also cause interference.
Option C: While correct, this is incomplete. Battery charging system and fuel delivery system also cause interference.
题目解析
The correct answer is D: All these choices are correct. What may cause receive interference to an HF transceiver installed in a vehicle includes: the battery charging system, the fuel delivery system, and the control computers. All three can generate electrical noise that interferes with HF reception. For amateur radio operators, this explains common mobile interference sources. Understanding this helps when troubleshooting mobile interference.
考试技巧
All three can cause mobile receive interference: battery charging system, fuel delivery system, control computers. When all listed systems can cause interference to mobile HF transceivers, 'all of the above' is usually the answer. All generate electrical noise.
记忆口诀
All three can cause interference: Battery charging, Fuel delivery, Control computers. Think 'A'll 'V'ehicle 'S'ystems can cause interference. All three generate electrical noise that interferes with HF reception. Common mobile interference sources.
实际应用示例
Your HF mobile transceiver experiences interference. Investigation reveals: (1) Battery charging system (alternator) generates noise, (2) Fuel delivery system (fuel pump, injectors) generates noise, (3) Control computers (ECU, various modules) generate noise. All three systems can cause interference to HF reception.
错误选项分析
Option A: While correct, this is incomplete. Fuel delivery system and control computers also cause interference. Option B: While correct, this is incomplete. Battery charging system and control computers also cause interference. Option C: While correct, this is incomplete. Battery charging system and fuel delivery system also cause interference.
知识点
Mobile interference, Battery charging system, Fuel delivery system, Control computers
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.