Deep Dive: E4D02
The correct answer is A: Spurious signals caused by cross modulation and desensitization from strong adjacent signals. Which of the following describes problems caused by poor dynamic range in a receiver is spurious signals caused by cross modulation and desensitization from strong adjacent signals. Poor dynamic range causes cross-modulation and desensitization. For amateur radio operators, this is important for receiver performance. Understanding this helps when troubleshooting receivers.
Why Other Answers Are Wrong
Option B: Incorrect. Oscillator instability requiring retuning and loss of opposite sideband isn't caused by poor dynamic range - cross-modulation and desensitization are. Oscillator instability isn't the problem. Option C: Incorrect. Poor weak signal reception from insufficient LO injection isn't caused by poor dynamic range - cross-modulation and desensitization are. Insufficient LO isn't the problem. Option D: Incorrect. Oscillator instability and severe audio distortion isn't caused by poor dynamic range - cross-modulation and desensitization are. Audio distortion isn't the problem.
Exam Tip
Poor dynamic range problems = spurious signals from cross modulation and desensitization by strong adjacent signals. Think 'P'oor 'D'ynamic 'R'ange = 'P'roblematic 'D'istortion 'R'esults (cross-mod/desense). Poor dynamic range causes cross-modulation and desensitization. Not oscillator instability, not insufficient LO, not audio distortion - just cross-mod and desensitization.
Memory Aid
Poor dynamic range problems = spurious signals from cross modulation and desensitization by strong adjacent signals. Think 'P'oor 'D'ynamic 'R'ange = 'C'ross-mod/'D'esensitization. Poor dynamic range causes cross-modulation and desensitization. Important for receiver performance.
Real-World Example
Poor dynamic range in a receiver: It causes spurious signals from cross modulation and desensitization from strong adjacent signals. Strong nearby signals can cross-modulate onto the desired signal and desensitize the receiver. This is the problem - cross-modulation and desensitization.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4D
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 E4D topic.