Ham Radio General Class Practice Test

What does the term "harmonics" refer to in radio transmission?

1. Multiple frequency outputs

2. Interference in signal

3. Distorted audio signals

4. Signal reflections

The correct answer is: Multiple frequency outputs

The term "harmonics" in radio transmission specifically refers to multiple frequency outputs that are integer multiples of a fundamental frequency. When a radio transmitter produces a signal at a certain frequency, it can also generate additional signals at frequencies that are multiples of that fundamental frequency, known as harmonics. For example, if the fundamental frequency is 100 MHz, the second harmonic would be at 200 MHz, and the third harmonic would be at 300 MHz. Harmonics are inherent in many electronic circuits, particularly those that use nonlinear components, as they tend to create additional frequencies when a signal is transmitted. Understanding harmonics is important for amateur radio operators because they can affect the purity of a transmitted signal and may lead to interference with other communication services if not properly managed. Other options involve concepts related to radio transmission but do not specifically define harmonics. Interference would refer to disruptions caused by external signals, distorted audio relates to the quality of the sound being transmitted, and signal reflections pertain to the phenomenon where signals bounce back off surfaces, which is distinct from harmonics.