FCC Exam Question: 6A5

When passing through areas of static charge, high voltages can accumulate on antennas which areinsulated from ground. What protects a connected receiver from damage?

A. Lightning arresters and suppressors
B. Protection diodes on receiver input
C. Capacitive coupling and static dissipative circuits
D. Any combination of the above
Correct Answer: D

Explanation: Protecting sensitive receiver inputs from static charge accumulation on an antenna requires a multi-layered approach. **Lightning arresters and suppressors** are designed to divert large static discharges, similar to lightning strikes, to ground when a specific voltage threshold is exceeded. They act as a primary defense against severe overvoltage events. **Protection diodes on receiver input** (e.g., PIN diodes, Zener diodes) are integrated into the receiver's circuitry. These diodes clamp any incoming voltage that exceeds safe operating levels, shunting the excess current to ground or the power supply rails, thus protecting the delicate input stages from damage. **Static dissipative circuits** typically involve a high-value resistor connected between the antenna input and ground. This resistor slowly and continuously bleeds off accumulated static charges, preventing them from building up to dangerous voltage levels in the first place, without significantly attenuating the desired radio signals. Since all these methods contribute to safeguarding a receiver from static charge, using any combination of them provides comprehensive protection.

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Includes Elements 1, 3, 6, 7R, 8, and 9.