What is the purpose of the antenna tuner?

• A. It increases transmitter output power.
• B. It alters the electrical characteristic of the antenna to match the frequency in use.
• C. It changes the modulation scheme automatically.
• D. It reduces antenna impedance to ground.

Answer: (B)

An antenna tuner is used to make the antenna system look like the transmitter’s intended impedance at the frequency you’re using. Since an antenna’s impedance changes with frequency, the tuner uses reactive components (inductors and capacitors) to transform the load so the transmitter sees a good match. This maximizes power transfer, reduces reflections (lower SWR), and protects the transmitter from standing waves. It doesn’t increase transmitter power by itself, it doesn’t change the modulation, and it doesn’t just pull impedance to ground—the tuner’s job is to shape the load the transmitter sees so the signal is delivered efficiently.