What is the most common frequency shift for RTTY emissions in the amateur HF bands?
The correct answer is B: 170 Hz. The most common frequency shift for RTTY emissions in the amateur HF bands is 170 Hz. This is the standard shift between mark and space frequencies for RTTY. For amateur radio operators, this ensures compatibility - everyone uses 170 Hz shift. Understanding this helps when operating RTTY.
Exam Tip
RTTY frequency shift = 170 Hz. Think 'R'TTY = '1'70 Hz 'S'hift 'S'tandard. Most common frequency shift for RTTY in amateur HF bands. Not 85, 425, or 850 Hz - 170 Hz is the standard.
Memory Aid
"RTTY frequency shift = 170 Hz. Think 'R'TTY = '1'70 Hz 'S'hift. Most common frequency shift for RTTY in amateur HF bands. Standard shift ensures compatibility. Not 85, 425, or 850 Hz."
Real-World Application
You operate RTTY on 20 meters. Your RTTY system uses 170 Hz shift between mark and space frequencies - this is the standard. Everyone uses 170 Hz shift, ensuring compatibility. If you used a different shift (like 85 Hz or 425 Hz), you wouldn't be able to communicate with other RTTY stations.
Key Concepts
Why Other Options Are Wrong
Option A (85 Hz): Incorrect. 85 Hz is half the standard shift - 170 Hz is the standard for amateur RTTY. 85 Hz is too narrow.
Option C (425 Hz): Incorrect. 425 Hz is wider than standard - 170 Hz is the standard shift. 425 Hz would cause compatibility issues.
Option D (850 Hz): Incorrect. 850 Hz is much wider than standard - 170 Hz is the standard shift. 850 Hz would cause severe compatibility problems.
题目解析
The correct answer is B: 170 Hz. The most common frequency shift for RTTY emissions in the amateur HF bands is 170 Hz. This is the standard shift between mark and space frequencies for RTTY. For amateur radio operators, this ensures compatibility - everyone uses 170 Hz shift. Understanding this helps when operating RTTY.
考试技巧
RTTY frequency shift = 170 Hz. Think 'R'TTY = '1'70 Hz 'S'hift 'S'tandard. Most common frequency shift for RTTY in amateur HF bands. Not 85, 425, or 850 Hz - 170 Hz is the standard.
记忆口诀
RTTY frequency shift = 170 Hz. Think 'R'TTY = '1'70 Hz 'S'hift. Most common frequency shift for RTTY in amateur HF bands. Standard shift ensures compatibility. Not 85, 425, or 850 Hz.
实际应用示例
You operate RTTY on 20 meters. Your RTTY system uses 170 Hz shift between mark and space frequencies - this is the standard. Everyone uses 170 Hz shift, ensuring compatibility. If you used a different shift (like 85 Hz or 425 Hz), you wouldn't be able to communicate with other RTTY stations.
错误选项分析
Option A (85 Hz): Incorrect. 85 Hz is half the standard shift - 170 Hz is the standard for amateur RTTY. 85 Hz is too narrow. Option C (425 Hz): Incorrect. 425 Hz is wider than standard - 170 Hz is the standard shift. 425 Hz would cause compatibility issues. Option D (850 Hz): Incorrect. 850 Hz is much wider than standard - 170 Hz is the standard shift. 850 Hz would cause severe compatibility problems.
知识点
RTTY, Frequency shift, 170 Hz shift, Digital modes
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.