Technician 2022-2026T9A04
What is a disadvantage of the short, flexible antenna supplied with most handheld radio transceivers, compared to a full-sized quarter-wave antenna?
A
Answer
Antennas and feed lines
Type
A
It has low efficiency
B
It transmits only circularly polarized signals
C
It is mechanically fragile
D
All these choices are correct
Answer Notes
The short, flexible antennas commonly known as "rubber ducks" are supplied with handheld radios for convenience and portability. To make them resonant at the proper frequency despite their small size, they use an internal coiled wire, which acts as an inductor.
The major tradeoff for this compact size is a significant loss in efficiency. A full-sized quarter-wave whip antenna has a larger physical aperture and radiates radio frequency energy much more effectively, meaning the short flexible antenna will give you less transmit and receive range.
The distractors are factually incorrect. These flexible antennas are mechanically rugged, not fragile, and they transmit linearly (vertically) polarized signals, not circularly polarized ones. Therefore, "All these choices are correct" is an incorrect trap.
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Which of the following describes a simple dipole oriented parallel to Earth's surface?
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Which of the following increases the resonant frequency of a dipole antenna?