Deep Dive: E4D04
The correct answer is B: A properly terminated circulator at the output of the repeater's transmitter. Which of the following is used to reduce or eliminate intermodulation interference in a repeater caused by a nearby transmitter is a properly terminated circulator at the output of the repeater's transmitter. Circulators provide isolation to prevent IMD. For amateur radio operators, this is important for repeater operation. Understanding this helps when reducing repeater interference.
Why Other Answers Are Wrong
Option A: Incorrect. Band-pass filter in feed line between transmitter and receiver isn't the solution - circulator at transmitter output is. Band-pass filter isn't the solution. Option C: Incorrect. Utilizing Class C final amplifier isn't the solution - circulator at transmitter output is. Class C amplifier isn't the solution. Option D: Incorrect. Utilizing Class D final amplifier isn't the solution - circulator at transmitter output is. Class D amplifier isn't the solution.
Exam Tip
Reduce IMD in repeater = properly terminated circulator at output of repeater's transmitter. Think 'R'educe 'I'MD = 'C'irculator 'I'solation. Circulators provide isolation to prevent IMD. Not band-pass filter, not Class C, not Class D - just circulator at transmitter output.
Memory Aid
Reduce IMD in repeater = properly terminated circulator at output of repeater's transmitter. Think 'R'educe 'I'MD = 'C'irculator. Circulators provide isolation to prevent IMD. Important for repeater operation.
Real-World Example
Reducing intermodulation interference in a repeater caused by a nearby transmitter: A properly terminated circulator at the output of the repeater's transmitter can be used. The circulator provides isolation, preventing nearby signals from entering the transmitter and causing IMD. This is the solution - circulator at transmitter output.
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.