What is the primary function of an external earth connection or ground rod?
The correct answer is B: Lightning charge dissipation. The primary function of an external earth connection or ground rod is lightning charge dissipation - providing a safe path for lightning strikes to flow into the ground, protecting equipment and structures.
Ground rods are primarily safety devices for lightning protection. When lightning strikes, the ground rod provides a low-resistance path for the massive electrical current to flow into the earth, preventing damage to equipment, structures, and people. While ground rods can also help with RF grounding and static buildup, their primary and most critical function is lightning protection. A proper ground rod system is essential for any antenna installation, especially tall structures like towers. The ground rod must be properly installed and connected to provide effective lightning protection.
Exam Tip
Ground rod primary function = Lightning protection. Remember: The primary function of an external earth connection or ground rod is lightning charge dissipation - providing a safe path for lightning to ground, protecting equipment and people.
Memory Aid
"**G**round **R**od **P**rimary = **L**ightning **P**rotection (think 'GRP = LP')"
Real-World Application
You install a tower with antennas. You drive ground rods around the base and connect them to the tower. When lightning strikes the tower, the ground rods provide a low-resistance path for the current to flow into the earth, protecting your equipment and preventing fires or damage. This lightning protection is the primary reason for the ground rod system.
FCC Part 97.13Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. While ground rods can help with static buildup, that's not their primary function. Lightning protection is the primary purpose.
Option C: Incorrect. Ground rods don't specifically reduce RF current flow between equipment. Their primary function is lightning protection, though they can help with RF grounding.
Option D: Incorrect. Ground rods don't protect breaker panels from power surges. That's what surge protectors do. Ground rods are for lightning protection.
题目解析
The correct answer is B: Lightning charge dissipation. The primary function of an external earth connection or ground rod is lightning charge dissipation - providing a safe path for lightning strikes to flow into the ground, protecting equipment and structures. Ground rods are primarily safety devices for lightning protection. When lightning strikes, the ground rod provides a low-resistance path for the massive electrical current to flow into the earth, preventing damage to equipment, structures, and people. While ground rods can also help with RF grounding and static buildup, their primary and most critical function is lightning protection. A proper ground rod system is essential for any antenna installation, especially tall structures like towers. The ground rod must be properly installed and connected to provide effective lightning protection.
考试技巧
Ground rod primary function = Lightning protection. Remember: The primary function of an external earth connection or ground rod is lightning charge dissipation - providing a safe path for lightning to ground, protecting equipment and people.
记忆口诀
**G**round **R**od **P**rimary = **L**ightning **P**rotection (think 'GRP = LP')
实际应用示例
You install a tower with antennas. You drive ground rods around the base and connect them to the tower. When lightning strikes the tower, the ground rods provide a low-resistance path for the current to flow into the earth, protecting your equipment and preventing fires or damage. This lightning protection is the primary reason for the ground rod system.
错误选项分析
Option A: Incorrect. While ground rods can help with static buildup, that's not their primary function. Lightning protection is the primary purpose. Option C: Incorrect. Ground rods don't specifically reduce RF current flow between equipment. Their primary function is lightning protection, though they can help with RF grounding. Option D: Incorrect. Ground rods don't protect breaker panels from power surges. That's what surge protectors do. Ground rods are for lightning protection.
知识点
Ground rod, Lightning protection, Earth connection, Safety
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.