Where should the negative power return of a mobile transceiver be connected in a vehicle?
The correct answer is A: At the 12 volt battery chassis ground. The negative power return (ground) of a mobile transceiver should be connected at the 12-volt battery chassis ground or directly to the battery negative terminal. This provides the best ground connection and minimizes ground loops and interference.
Connecting the negative lead directly to the battery or battery ground ensures a low-resistance path for return current. This is important because the negative lead carries the return current, and any resistance in this path can cause voltage drop and potential interference issues. Connecting to the battery ground (or battery negative terminal) provides the most direct, low-resistance connection, which is essential for proper operation and minimizing RF interference.
Exam Tip
Mobile negative = Battery ground. Remember: Connect the mobile transceiver's negative power return to the 12-volt battery chassis ground (or battery negative terminal) for the best connection.
Memory Aid
"**M**obile **N**egative = **B**attery **G**round (think 'MN = BG' = Battery Ground)"
Real-World Application
You're installing a mobile transceiver. You run the positive wire to the battery positive terminal (or fuse block). For the negative wire, you connect it directly to the battery negative terminal or to the battery's chassis ground point. This provides a direct, low-resistance path for the return current, ensuring proper operation and minimizing potential interference issues.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. The antenna mount is not the proper location for power ground. Antenna mounts are for RF ground/counterpoise, not DC power return.
Option C: Incorrect. 'Any metal part' is too vague and might not provide a good ground connection. The battery ground is the proper location.
Option D: Incorrect. The mounting bracket might provide some connection, but the battery ground is the proper, direct connection point.
题目解析
The correct answer is A: At the 12 volt battery chassis ground. The negative power return (ground) of a mobile transceiver should be connected at the 12-volt battery chassis ground or directly to the battery negative terminal. This provides the best ground connection and minimizes ground loops and interference. Connecting the negative lead directly to the battery or battery ground ensures a low-resistance path for return current. This is important because the negative lead carries the return current, and any resistance in this path can cause voltage drop and potential interference issues. Connecting to the battery ground (or battery negative terminal) provides the most direct, low-resistance connection, which is essential for proper operation and minimizing RF interference.
考试技巧
Mobile negative = Battery ground. Remember: Connect the mobile transceiver's negative power return to the 12-volt battery chassis ground (or battery negative terminal) for the best connection.
记忆口诀
**M**obile **N**egative = **B**attery **G**round (think 'MN = BG' = Battery Ground)
实际应用示例
You're installing a mobile transceiver. You run the positive wire to the battery positive terminal (or fuse block). For the negative wire, you connect it directly to the battery negative terminal or to the battery's chassis ground point. This provides a direct, low-resistance path for the return current, ensuring proper operation and minimizing potential interference issues.
错误选项分析
Option B: Incorrect. The antenna mount is not the proper location for power ground. Antenna mounts are for RF ground/counterpoise, not DC power return. Option C: Incorrect. 'Any metal part' is too vague and might not provide a good ground connection. The battery ground is the proper location. Option D: Incorrect. The mounting bracket might provide some connection, but the battery ground is the proper, direct connection point.
知识点
Mobile installation, Negative ground, Battery connection, Power wiring
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.