What is a disadvantage of the short, flexible antenna supplied with most handheld radio transceivers, compared to a full-sized quarter-wave antenna?
The correct answer is A: It has low efficiency. A disadvantage of the short, flexible antenna supplied with most handheld radio transceivers (compared to a full-sized quarter-wave antenna) is that it has low efficiency. Short antennas are much smaller than a quarter wavelength, making them inefficient radiators. Much of the power is lost as heat or reflected back to the transmitter rather than being radiated. For amateur radio operators, understanding this limitation helps explain why handheld radios have limited range and why external antennas improve performance. The trade-off is convenience versus performance.
Exam Tip
Short flexible antenna = low efficiency. Think 'S'hort antenna = 'S'mall efficiency. Much smaller than quarter-wave, so inefficient - power is lost, not radiated. The primary disadvantage is efficiency, not polarization or fragility.
Memory Aid
"Short flexible antenna = low efficiency. Think 'S'hort antenna = 'S'mall efficiency. Much smaller than quarter-wave, so inefficient radiator. Power is lost rather than radiated, limiting range."
Real-World Application
Your handheld transceiver comes with a short flexible 'rubber duck' antenna. Compared to a full-sized quarter-wave antenna (about 19 inches for 2 meters), this short antenna is very inefficient - perhaps only 10-20% of your power is actually radiated, with the rest lost as heat or reflected. This limits your range. Using an external full-sized antenna dramatically improves efficiency and range.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Short flexible antennas don't transmit only circularly polarized signals - they can be linearly polarized. The issue is efficiency, not polarization type.
Option C: Incorrect. While some short antennas might be fragile, this isn't the primary disadvantage compared to efficiency. Many flexible antennas are quite durable.
Option D: Incorrect. Since B and C are not the main disadvantages, 'all of the above' cannot be correct. Low efficiency is the primary disadvantage.
题目解析
The correct answer is A: It has low efficiency. A disadvantage of the short, flexible antenna supplied with most handheld radio transceivers (compared to a full-sized quarter-wave antenna) is that it has low efficiency. Short antennas are much smaller than a quarter wavelength, making them inefficient radiators. Much of the power is lost as heat or reflected back to the transmitter rather than being radiated. For amateur radio operators, understanding this limitation helps explain why handheld radios have limited range and why external antennas improve performance. The trade-off is convenience versus performance.
考试技巧
Short flexible antenna = low efficiency. Think 'S'hort antenna = 'S'mall efficiency. Much smaller than quarter-wave, so inefficient - power is lost, not radiated. The primary disadvantage is efficiency, not polarization or fragility.
记忆口诀
Short flexible antenna = low efficiency. Think 'S'hort antenna = 'S'mall efficiency. Much smaller than quarter-wave, so inefficient radiator. Power is lost rather than radiated, limiting range.
实际应用示例
Your handheld transceiver comes with a short flexible 'rubber duck' antenna. Compared to a full-sized quarter-wave antenna (about 19 inches for 2 meters), this short antenna is very inefficient - perhaps only 10-20% of your power is actually radiated, with the rest lost as heat or reflected. This limits your range. Using an external full-sized antenna dramatically improves efficiency and range.
错误选项分析
Option B: Incorrect. Short flexible antennas don't transmit only circularly polarized signals - they can be linearly polarized. The issue is efficiency, not polarization type. Option C: Incorrect. While some short antennas might be fragile, this isn't the primary disadvantage compared to efficiency. Many flexible antennas are quite durable. Option D: Incorrect. Since B and C are not the main disadvantages, 'all of the above' cannot be correct. Low efficiency is the primary disadvantage.
知识点
Handheld antennas, Antenna efficiency, Short antennas, Mobile antennas
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.