FCC Question Pool Review

Technician Class (Element 2) • 2022-2026

Switch License

Question T7B11

From subelement T7 - T7B

T7B11
Answer: C

What is a symptom of RF feedback in a transmitter or transceiver?

AExcessive SWR at the antenna connection
BThe transmitter will not stay on the desired frequency
CReports of garbled, distorted, or unintelligible voice transmissions
DFrequent blowing of power supply fuses

Why is this correct?

RF feedback occurs when transmitted RF energy gets back into the microphone or audio circuits, creating a feedback loop where your signal interferes with its own audio input. This manifests as garbled, distorted, or unintelligible voice transmissions that other stations report hearing. Options A, B, and D describe different problems: excessive SWR indicates antenna system issues, frequency drift suggests oscillator problems, and blown fuses point to power supply overload.

Memory tip

RF feedback creates an audio feedback loop, similar to when a microphone picks up sound from speakers it's connected to. The key pattern: when RF energy contaminates audio circuits, the symptom is always audio-related distortion that affects transmission quality, not hardware failures or frequency stability issues.

Learn more

RF feedback requires proper station RF management through grounding, ferrite chokes on cables, and adequate shielding of audio equipment. Poor antenna placement can increase RF levels in the operating position. Understanding RF feedback helps with broader emission standards compliance under Part 97, as RF contamination can create spurious emissions and degrade signal quality beyond your station's control room.

Think about it

Why do you think RF feedback specifically affects audio quality rather than causing equipment damage like blown fuses or frequency instability?