FCC Question Pool Review

Technician Class (Element 2) • 2022-2026

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Question T0B06

From subelement T0 - T0B

T0B06
Answer: D

What is the minimum safe distance from a power line to allow when installing an antenna?

AAdd the height of the antenna to the height of the power line and multiply by a factor of 1.5
BThe height of the power line above ground
C1/2 wavelength at the operating frequency
DEnough so that if the antenna falls, no part of it can come closer than 10 feet to the power wires

Why is this correct?

Answer D is correct because it establishes a practical safety buffer that accounts for antenna failure. The 10-foot clearance rule ensures that even if your antenna system completely falls over, no part will contact power lines. Options A, B, and C all miss this critical failure scenario - they focus on mathematical formulas or technical measurements rather than the real-world safety principle that antennas can and do fall.

Memory tip

Remember the 'fall zone' concept: always plan for equipment failure when working near hazards. This same thinking applies to tree removal, construction, and many other safety situations - calculate the worst-case scenario, not just normal operation.

Learn more

Power lines carry thousands of volts and represent the greatest electrocution hazard in amateur radio installation. The 10-foot rule originated from electrical industry standards recognizing that high voltage can arc across air gaps. Professional antenna installers use this same clearance requirement. This isn't just about your antenna touching the wire - electricity can jump across smaller gaps, especially in humid conditions or during storms when insulation breaks down.

Think about it

Why do you think the rule focuses on what happens 'if the antenna falls' rather than just maintaining clearance during normal operation?