Deep Dive: E4E04
The correct answer is D: By installing ferrite chokes on the charging system leads. How can conducted noise from an automobile battery charging system be suppressed is by installing ferrite chokes on the charging system leads. Ferrite chokes block RF noise on power leads. For amateur radio operators, this is important for mobile operation. Understanding this helps when reducing mobile noise.
Why Other Answers Are Wrong
Option A: Incorrect. Installing filter capacitors in series with alternator leads isn't correct - ferrite chokes on leads suppress noise. Series capacitors isn't the method. Option B: Incorrect. Installing noise suppression resistor and blocking capacitor at battery isn't correct - ferrite chokes on leads suppress noise. Resistor/capacitor at battery isn't the method. Option C: Incorrect. Installing high-pass filter in series with radio power lead and low-pass filter in parallel with antenna feed line isn't correct - ferrite chokes on leads suppress noise. Filters on radio/antenna isn't the method.
Exam Tip
Suppress conducted noise from auto charging system = install ferrite chokes on charging system leads. Think 'C'onducted 'N'oise = 'C'hokes on 'N'oise source leads. Ferrite chokes block RF noise on power leads. Not series capacitors, not resistor/capacitor at battery, not filters on radio/antenna - just ferrite chokes on charging leads.
Memory Aid
Suppress conducted noise from auto charging system = install ferrite chokes on charging system leads. Think 'C'onducted 'N'oise = 'F'errite 'C'hokes. Ferrite chokes block RF noise on power leads. Important for mobile operation.
Real-World Example
Suppressing conducted noise from an automobile battery charging system: Install ferrite chokes on the charging system leads. The ferrite chokes block RF noise from traveling along the power leads. This is the method - ferrite chokes on charging system leads.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E4E
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 E4E topic.