What is the purpose of an antenna tuner?
The correct answer is C: Increase power transfer from the transmitter to the feed line. The purpose of an antenna tuner is to increase power transfer from the transmitter to the feed line. An antenna tuner matches the antenna impedance to the transmitter output impedance (typically 50 ohms), maximizing power transfer. For amateur radio operators, this is the primary function of antenna tuners. Understanding this helps when using tuners.
Exam Tip
Antenna tuner purpose = increase power transfer from transmitter to feed line. Think 'A'ntenna 'T'uner = 'A'chieves 'T'ransfer (impedance matching). Matches antenna impedance to transmitter output, maximizing power transfer. Not SWR reduction, not power dissipation reduction - just power transfer.
Memory Aid
"Antenna tuner purpose = increase power transfer from transmitter to feed line. Think 'A'ntenna 'T'uner = 'A'chieves 'T'ransfer. Matches antenna impedance to transmitter output, maximizing power transfer. Primary function of antenna tuners."
Real-World Application
Your antenna presents 25 ohms impedance, but your transmitter wants 50 ohms. You use an antenna tuner to match the impedance. The tuner transforms the 25-ohm antenna impedance to 50 ohms at the tuner output, maximizing power transfer from the transmitter to the feed line. This is the tuner's primary purpose.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Antenna tuners don't reduce SWR in the feed line - they match impedance at the tuner, but SWR in the feed line may still exist. Tuners match at their location.
Option B: Incorrect. Antenna tuners don't reduce power dissipation in the feed line - they match impedance to increase power transfer. Power dissipation depends on SWR and feed line loss.
Option D: Incorrect. Since A and B are not correct, 'all of the above' cannot be correct. Only power transfer increase is the primary purpose.
题目解析
The correct answer is C: Increase power transfer from the transmitter to the feed line. The purpose of an antenna tuner is to increase power transfer from the transmitter to the feed line. An antenna tuner matches the antenna impedance to the transmitter output impedance (typically 50 ohms), maximizing power transfer. For amateur radio operators, this is the primary function of antenna tuners. Understanding this helps when using tuners.
考试技巧
Antenna tuner purpose = increase power transfer from transmitter to feed line. Think 'A'ntenna 'T'uner = 'A'chieves 'T'ransfer (impedance matching). Matches antenna impedance to transmitter output, maximizing power transfer. Not SWR reduction, not power dissipation reduction - just power transfer.
记忆口诀
Antenna tuner purpose = increase power transfer from transmitter to feed line. Think 'A'ntenna 'T'uner = 'A'chieves 'T'ransfer. Matches antenna impedance to transmitter output, maximizing power transfer. Primary function of antenna tuners.
实际应用示例
Your antenna presents 25 ohms impedance, but your transmitter wants 50 ohms. You use an antenna tuner to match the impedance. The tuner transforms the 25-ohm antenna impedance to 50 ohms at the tuner output, maximizing power transfer from the transmitter to the feed line. This is the tuner's primary purpose.
错误选项分析
Option A: Incorrect. Antenna tuners don't reduce SWR in the feed line - they match impedance at the tuner, but SWR in the feed line may still exist. Tuners match at their location. Option B: Incorrect. Antenna tuners don't reduce power dissipation in the feed line - they match impedance to increase power transfer. Power dissipation depends on SWR and feed line loss. Option D: Incorrect. Since A and B are not correct, 'all of the above' cannot be correct. Only power transfer increase is the primary purpose.
知识点
Antenna tuner, Power transfer, Impedance matching, Transmitter to feed line
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.