Deep Dive: E9C08
The correct answer is C: A half-wave dipole with an additional parallel wire connecting its two ends. A folded dipole antenna is a half-wave dipole with an additional parallel wire connecting its two ends. The two wires form a loop, with the feed point at the center of one wire. A folded dipole looks like a standard dipole with an extra wire running parallel and connected at both ends. This creates a loop structure. The feed point is typically at the center of one of the wires. The folding increases the impedance compared to a simple dipole and can improve bandwidth. Folded dipoles are commonly used in Yagi antennas as driven elements because the higher impedance (about 300 ohms) can be easier to match in some configurations.
Why Other Answers Are Wrong
Option A: Incorrect. A folded dipole is a half-wave dipole, not a quarter-wave. The total length is half a wavelength. Option B: Incorrect. The ends aren't folded down 90 degrees. The additional wire runs parallel and connects the ends, creating a loop. Option D: Incorrect. A folded dipole isn't specifically configured for forward gain. It's a driven element that can be used in various antennas, including Yagis which do have gain.
Exam Tip
Folded dipole = Half-wave with parallel wire connecting ends. Remember: A folded dipole is a half-wave dipole with an additional parallel wire connecting its two ends, forming a loop structure.
Memory Aid
**F**olded **D**ipole = **H**alf-**W**ave + **P**arallel **W**ire (think 'FD = HW+PW')
Real-World Example
You build a folded dipole. You start with a standard half-wave dipole, then add a second wire running parallel to it. You connect both ends of the two wires together, creating a loop. The feed point is at the center of one wire. This folded structure has higher impedance (about 300 ohms) than a simple dipole.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E9C
Reference: FCC Part 97.3
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E9C topic.