Which type of voice mode is often used for long-distance (weak signal) contacts on the VHF and UHF bands?

• A. Amplitude modulation
• B. Single sideband
• C. Frequency modulation
• D. Digital modes

Answer: (B)

Single sideband (SSB) is a voice mode that excels for long-distance communication, particularly on VHF and UHF bands. This mode is an efficient form of amplitude modulation (AM) that only transmits a single sideband (either upper or lower) of the AM signal, rather than both the upper and lower sidebands along with the carrier wave.

By discarding the carrier and one of the sidebands, SSB significantly reduces bandwidth and power consumption, making it ideal for weak signal conditions. This efficiency allows operators to communicate effectively over greater distances, as SSB can be more adept at cutting through noise and reducing interference compared to other voice modes.

The other modes listed have their specific use cases: amplitude modulation is broader and less efficient for weak signal work, frequency modulation is typically used for local communications where clarity is prioritized over range, and while digital modes can also be very effective for weak signals, they are not primarily voice modes, which is the focus of the question.