Ham Radio General Class Practice Test

Which of the following modulations is primarily used to achieve greater distance in radio communication?

1. Amplitude modulation

2. Frequency modulation

3. Single sideband modulation

4. Pulsed modulation

The correct answer is: Single sideband modulation

Single Sideband Modulation (SSB) is the correct answer because it is a refinement of amplitude modulation that effectively reduces the bandwidth of the transmitted signal and improves power efficiency. By eliminating one of the sidebands and the carrier wave, SSB allows for more efficient use of available spectrum and allows for greater distance in communication. SSB provides advantages such as: 1. **Increased Range**: The reduction in bandwidth allows SSB signals to travel longer distances, especially under conditions like low ionospheric reflection. 2. **Improved Efficiency**: SSB uses power more effectively. Since it doesn't transmit two sidebands, more power is directed toward the information being sent rather than wasted in transmission. 3. **Signal Clarity**: SSB can also provide clearer signals over long distances, as it is less susceptible to static and interference compared to traditional AM. While amplitude modulation does allow for long-range communication, it is generally less efficient than SSB. Frequency modulation is often used for high-fidelity audio transmissions and local communications rather than long-distance ones. Pulsed modulation can be suitable for specific applications like radar, but it does not directly relate to achieving greater distance in the same way that SSB does. Hence, SSB is