Deep Dive: E4C02
The correct answer is A: A front-end filter or preselector. Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals is a front-end filter or preselector. Front-end filters reject out-of-band signals before they enter the receiver. For amateur radio operators, this is important for receiver performance. Understanding this helps when reducing interference.
Why Other Answers Are Wrong
Option B: Incorrect. Narrow IF filter doesn't eliminate out-of-band signals - front-end filter does. IF filter is after mixing. Option C: Incorrect. Notch filter doesn't eliminate out-of-band signals - front-end filter does. Notch filter is for specific frequencies. Option D: Incorrect. Product detector doesn't eliminate out-of-band signals - front-end filter does. Product detector is for demodulation.
Exam Tip
Eliminate out-of-band interference = front-end filter or preselector. Think 'O'ut-of-'B'and = 'O'utside 'B'efore receiver (front-end). Front-end filters reject out-of-band signals before they enter the receiver. Not IF filter, not notch filter, not product detector - just front-end filter.
Memory Aid
Eliminate out-of-band interference = front-end filter or preselector. Think 'O'ut-of-'B'and = 'F'ront-'E'nd filter. Front-end filters reject out-of-band signals before they enter the receiver. Important for receiver performance.
Real-World Example
Eliminating interference from strong out-of-band signals: A front-end filter or preselector can be effective. These filters are placed at the receiver input and reject out-of-band signals before they can enter and cause problems. This is the circuit - front-end filter or preselector.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4C
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 E4C topic.