Deep Dive: T9A12
The correct answer is A: It has more gain than a 1/4-wavelength antenna. An advantage of a 5/8 wavelength whip antenna for VHF or UHF mobile service is that it has more gain than a 1/4-wavelength antenna. A 5/8 wave antenna typically provides about 3-4 dB gain compared to a 1/4 wave antenna. This increased gain improves both transmit and receive performance. For amateur radio operators, 5/8 wave antennas are popular for mobile installations where you want better performance than a 1/4 wave but don't have space for a full 1/2 wave. Understanding this helps when selecting mobile antennas.
Why Other Answers Are Wrong
Option B: Incorrect. A 5/8 wave antenna actually radiates at a lower angle (better for distance), not a very high angle. High angles are for local coverage, which isn't an advantage. Option C: Incorrect. A 5/8 wave antenna doesn't eliminate distortion from reflected signals - that's not related to antenna length. Distortion comes from multipath, not antenna design. Option D: Incorrect. 5/8 wave doesn't have 10 times the power gain - it has about 3-4 dB gain, which is about 2-2.5 times, not 10 times.
Exam Tip
5/8 wave advantage = more gain than 1/4 wave. Think '5'/8 wave = '5' times better? No, but 'M'ore gain than 1/4 wave (~3-4 dB). Not about high angle, distortion elimination, or 10x power - just more gain.
Memory Aid
5/8 wave advantage = more gain than 1/4 wave. Think '5'/8 wave = 'M'ore gain (~3-4 dB) than 1/4 wave. Longer antenna provides better performance for mobile use.
Real-World Example
You're choosing a mobile antenna for 2 meters. A 1/4 wave antenna is 19 inches with about 0 dB gain. A 5/8 wave antenna is about 48 inches with 3-4 dB gain. The longer 5/8 wave gives you noticeably better range and signal strength, making it worth the extra length for mobile operation where performance matters.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T9A
Reference: 2022-2026 Question Pool · T9 - Antennas and feed lines
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T9A topic.