Deep Dive: T0B05
The correct answer is B: Prevent loosening of the turnbuckle from vibration. The purpose of a safety wire through a turnbuckle used to tension guy lines is to prevent loosening of the turnbuckle from vibration. Turnbuckles can loosen over time due to vibration from wind, antennas, or other sources. Safety wire (lock wire) prevents the turnbuckle from rotating and loosening. For amateur radio operators, this is essential for maintaining tower stability. Understanding this helps maintain safe tower installations.
Why Other Answers Are Wrong
Option A: Incorrect. Safety wire doesn't secure the guy line if the turnbuckle breaks - if the turnbuckle breaks, the safety wire won't hold the load. The guy line itself must be strong enough. Option C: Incorrect. Safety wire doesn't provide a ground path - it's too small and not designed for grounding. Grounding is done with proper ground wires. Option D: Incorrect. Safety wire doesn't measure tension - that's done with tension gauges or by measuring guy line sag. Safety wire prevents loosening, it doesn't measure anything.
Exam Tip
Safety wire = prevents turnbuckle loosening. Think 'S'afety 'W'ire = 'S'tops 'W'orking loose. Prevents turnbuckle from rotating due to vibration. Not for securing if broken, not for grounding, not for measuring tension.
Memory Aid
Safety wire = prevents turnbuckle loosening. Think 'S'afety 'W'ire = 'S'tops 'W'orking loose. Prevents vibration from causing turnbuckle to unscrew. Essential for maintaining guy line tension.
Real-World Example
Your tower guy lines use turnbuckles for tensioning. You install safety wire through the turnbuckle to prevent it from rotating. Wind and vibration would otherwise cause the turnbuckle to slowly unscrew over time, loosening the guy line and compromising tower stability. The safety wire locks the turnbuckle in place.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T0B
Reference: 2022-2026 Question Pool · T0 - Safety
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T0B topic.