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

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

The correct answer is C: SSB. The correct answer is C: SSB. Single sideband (SSB) is often used for long-distance (weak signal) contacts on VHF and UHF bands. SSB is more efficient than FM for weak-signal work because it uses less bandwidth (about 3 kHz vs 15 kHz for FM) and puts all power into the information-carrying sideband. This makes SSB better for weak-signal propagation modes like tropospheric ducting, sporadic E, and meteor scatter. For amateur radio operators, SSB on VHF/UHF is essential for weak-signal work, DX, and contesting where maximum efficiency is needed.

Previous Next

Deep Dive: T8A03

The correct answer is C: SSB. Single sideband (SSB) is often used for long-distance (weak signal) contacts on VHF and UHF bands. SSB is more efficient than FM for weak-signal work because it uses less bandwidth (about 3 kHz vs 15 kHz for FM) and puts all power into the information-carrying sideband. This makes SSB better for weak-signal propagation modes like tropospheric ducting, sporadic E, and meteor scatter. For amateur radio operators, SSB on VHF/UHF is essential for weak-signal work, DX, and contesting where maximum efficiency is needed.

Why Other Answers Are Wrong

Option A (FM): Incorrect. FM is used for local communications and repeaters but is less efficient for weak-signal work. SSB is better for long-distance weak-signal contacts. Option B (DRM): Incorrect. DRM (Digital Radio Mondiale) is a digital broadcasting system, not commonly used for amateur VHF/UHF weak-signal work. Option D (PM): Incorrect. Phase modulation is similar to FM but not commonly used for VHF/UHF weak-signal work. SSB is the standard.

Exam Tip

VHF/UHF weak-signal = SSB. Think 'W'eak 'S'ignal = 'W'orks with 'S'SB. SSB is more efficient (narrower bandwidth, all power in sideband) making it better for weak-signal and long-distance contacts than FM.

Memory Aid

VHF/UHF weak-signal = SSB. Think 'W'eak 'S'ignal = 'W'orks with 'S'SB. More efficient than FM for long-distance weak-signal contacts. Narrow bandwidth and efficient power use.

Real-World Example

During a sporadic E opening on 6 meters, operators use SSB for weak-signal contacts hundreds of miles away. SSB's narrow bandwidth (3 kHz) and efficient use of power make it possible to copy signals that would be inaudible on FM. The same signal that's readable on SSB might be completely lost in the noise on FM due to FM's wider bandwidth and capture effect.

Source & Coverage

Question Pool: 2026-2030 Question Pool

Subelement: T8A

Reference: 2026-2030 Question Pool · T8 - Signals and emissions

Key Concepts

SSB on VHF/UHF Weak signal operation Long-distance contacts VHF/UHF SSB

Official Pool Source

Question text and answer key are synchronized with the current NCVEC Technician Class pool and mapped to the T8A topic.