Deep Dive: E4A08
The correct answer is D: All these choices are correct. Which of the following is used to measure SWR includes: directional wattmeter, vector network analyzer, and antenna analyzer. All three can measure SWR. For amateur radio operators, this is important for test equipment. Understanding this helps when measuring SWR.
Why Other Answers Are Wrong
Option A: While correct, this is incomplete. Vector network analyzer and antenna analyzer can also measure SWR. Option B: While correct, this is incomplete. Directional wattmeter and antenna analyzer can also measure SWR. Option C: While correct, this is incomplete. Directional wattmeter and vector network analyzer can also measure SWR.
Exam Tip
All three can measure SWR: directional wattmeter, vector network analyzer, antenna analyzer. When all listed instruments can measure SWR, 'all of the above' is usually the answer. All are valid SWR measurement tools.
Memory Aid
All three can measure SWR: Directional wattmeter, Vector network analyzer, Antenna analyzer. Think 'A'll 'S'WR 'M'easurement tools. All three are valid SWR measurement instruments. Important for test equipment.
Real-World Example
Measuring SWR: A directional wattmeter can measure forward and reflected power to calculate SWR. A vector network analyzer can measure SWR directly. An antenna analyzer can measure SWR and impedance. All three can measure SWR. This is what can measure SWR - all these instruments.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4A
Reference: 2024-2028 Question Pool · E4 - Amateur Practices
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E4A topic.