What antenna polarization is normally used for long-distance CW and SSB contacts on the VHF and UHF bands?
The correct answer is C: Horizontal. For long-distance CW and SSB contacts on VHF and UHF bands, horizontal polarization is normally used. This is because horizontal polarization works better for weak-signal, long-distance communications on these bands.
Horizontal polarization is preferred for weak-signal work (like meteor scatter, moonbounce, or tropospheric ducting) because it typically provides better performance for these propagation modes. Most weak-signal operators use horizontally polarized antennas (like horizontal Yagis) for VHF/UHF DX work. Vertical polarization is more common for local FM communications and repeaters, but horizontal is the standard for long-distance weak-signal operations.
Exam Tip
VHF/UHF long-distance = Horizontal polarization. Remember: For long-distance CW and SSB on VHF/UHF, use horizontal polarization. Vertical is for local FM, horizontal is for weak-signal DX.
Memory Aid
"**L**ong **D**istance **V**HF/**U**HF = **H**orizontal (think 'LDVU = H' = Long Distance VHF/UHF = Horizontal)"
Real-World Application
You're trying to work a station 500 miles away on 2-meter SSB using tropospheric ducting. You use a horizontally polarized Yagi antenna pointed in their direction. Most weak-signal operators on VHF/UHF use horizontal polarization for these long-distance contacts, so matching their polarization gives you the best signal strength and communication reliability.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Right-hand circular polarization is used for some satellite work, but horizontal is standard for terrestrial weak-signal work.
Option B: Incorrect. Left-hand circular polarization is used for some satellite work, but horizontal is standard for terrestrial weak-signal work.
Option D: Incorrect. Vertical polarization is common for local FM and repeaters, but horizontal is preferred for long-distance weak-signal work.
题目解析
The correct answer is C: Horizontal. For long-distance CW and SSB contacts on VHF and UHF bands, horizontal polarization is normally used. This is because horizontal polarization works better for weak-signal, long-distance communications on these bands. Horizontal polarization is preferred for weak-signal work (like meteor scatter, moonbounce, or tropospheric ducting) because it typically provides better performance for these propagation modes. Most weak-signal operators use horizontally polarized antennas (like horizontal Yagis) for VHF/UHF DX work. Vertical polarization is more common for local FM communications and repeaters, but horizontal is the standard for long-distance weak-signal operations.
考试技巧
VHF/UHF long-distance = Horizontal polarization. Remember: For long-distance CW and SSB on VHF/UHF, use horizontal polarization. Vertical is for local FM, horizontal is for weak-signal DX.
记忆口诀
**L**ong **D**istance **V**HF/**U**HF = **H**orizontal (think 'LDVU = H' = Long Distance VHF/UHF = Horizontal)
实际应用示例
You're trying to work a station 500 miles away on 2-meter SSB using tropospheric ducting. You use a horizontally polarized Yagi antenna pointed in their direction. Most weak-signal operators on VHF/UHF use horizontal polarization for these long-distance contacts, so matching their polarization gives you the best signal strength and communication reliability.
错误选项分析
Option A: Incorrect. Right-hand circular polarization is used for some satellite work, but horizontal is standard for terrestrial weak-signal work. Option B: Incorrect. Left-hand circular polarization is used for some satellite work, but horizontal is standard for terrestrial weak-signal work. Option D: Incorrect. Vertical polarization is common for local FM and repeaters, but horizontal is preferred for long-distance weak-signal work.
知识点
Horizontal polarization, VHF/UHF, Weak-signal, Long-distance communications
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.