Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E4E
E4E07E4E

Which of the following can cause shielded cables to radiate or receive interference?

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Deep Dive: E4E07

The correct answer is B: Common-mode currents on the shield and conductors. Which of the following can cause shielded cables to radiate or receive interference is common-mode currents on the shield and conductors. Common-mode currents cause shielded cables to radiate. For amateur radio operators, this is important for reducing interference. Understanding this helps when troubleshooting cable radiation.

Why Other Answers Are Wrong

Option A: Incorrect. Low inductance ground connections at both ends doesn't cause radiation - common-mode currents do. Low inductance ground isn't the cause. Option C: Incorrect. Use of braided shielding material doesn't cause radiation - common-mode currents do. Braided shielding isn't the cause. Option D: Incorrect. Tying all grounds to common point causing differential-mode currents isn't the cause - common-mode currents cause radiation. Differential-mode isn't the cause.

Exam Tip

Shielded cable radiation cause = common-mode currents on shield and conductors. Think 'S'hielded 'C'able 'R'adiation = 'C'ommon-'M'ode 'C'urrents. Common-mode currents cause shielded cables to radiate. Not low inductance ground, not braided shielding, not differential-mode - just common-mode currents.

Memory Aid

Shielded cable radiation cause = common-mode currents on shield and conductors. Think 'S'hielded 'C'able = 'C'ommon-mode. Common-mode currents cause shielded cables to radiate. Important for reducing interference.

Real-World Example

Shielded cables: They can radiate or receive interference when common-mode currents flow on the shield and conductors. Common-mode currents (currents flowing in the same direction on all conductors) can cause the cable to act as an antenna. This is the cause - common-mode currents.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E4E

Reference: 2024-2028 Question Pool · E4 - Amateur Practices

Key Concepts

Shielded cables Radiate or receive interference Common-mode currents Shield and conductors

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E4E topic.