Ham Radio General Class Practice Test

Which mode of voice communication is most commonly used on the high frequency amateur bands?

1. Frequency modulation

2. Double sideband

3. Single sideband

4. Phase modulation

The correct answer is: Single sideband

Single sideband (SSB) is the most commonly used mode of voice communication on the high frequency (HF) amateur bands due to its efficiency and effectiveness in long-distance communication. One of the primary reasons for SSB's popularity is its ability to transmit audio with less bandwidth compared to other modes. It occupies about half the bandwidth of frequency modulation (FM) and double sideband amplitude modulation (DSB), allowing for more channels to fit within the same frequency range. This efficiency is crucial on HF bands, where available bandwidth is limited. Moreover, SSB has a greater range and clarity for voice communication, especially under poor propagation conditions that are typical on HF frequencies. Since SSB uses only one sideband, the power required for the transmission is also reduced, allowing operators to communicate over vast distances with minimal power consumption. In contrast, frequency modulation is more commonly used on VHF and UHF bands due to its noise immunity but is less efficient in terms of bandwidth usage on HF. Double sideband carries more power and can result in greater interference, which can be problematic in crowded bands. Phase modulation, while an interesting technique, is not widely implemented for voice communication in amateur radio compared to SSB. Overall, these factors contribute