Deep Dive: E4B05
The correct answer is B: Short circuit, open circuit, and 50 ohms. What three test loads are used to calibrate an RF vector network analyzer is short circuit, open circuit, and 50 ohms. These three loads are used for VNA calibration. For amateur radio operators, this is important for test equipment. Understanding this helps when calibrating network analyzers.
Why Other Answers Are Wrong
Option A: Incorrect. 50, 75, and 90 ohms isn't correct - VNA calibration uses short, open, and 50 ohms. 75/90 ohms isn't used. Option C: Incorrect. Short, open, and resonant circuit isn't correct - VNA calibration uses short, open, and 50 ohms. Resonant circuit isn't used. Option D: Incorrect. 50 ohms through different cable lengths isn't correct - VNA calibration uses short, open, and 50 ohms. Cable lengths isn't the method.
Exam Tip
VNA calibration loads = short circuit, open circuit, and 50 ohms. Think 'V'NA 'C'alibration = 'S'hort, 'O'pen, '5'0 ohms. These three loads are used for VNA calibration. Not 75/90 ohms, not resonant circuit, not cable lengths - just short, open, 50 ohms.
Memory Aid
VNA calibration loads = short circuit, open circuit, and 50 ohms. Think 'V'NA 'C'alibration = 'S'hort, 'O'pen, '5'0 ohms. These three loads are used for VNA calibration. Important for test equipment.
Real-World Example
Calibrating an RF vector network analyzer: Three test loads are used - short circuit, open circuit, and 50 ohms. These three known impedances allow the VNA to calibrate its measurements. This is the calibration method - short, open, and 50 ohms.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4B
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 E4B topic.