What is the standard sideband for JT65, JT9, FT4, or FT8 digital signal when using AFSK?
The correct answer is B: USB. The standard sideband for JT65, JT9, FT4, or FT8 digital signals when using AFSK is USB (Upper Sideband). These digital modes use USB on HF, similar to voice on higher HF bands. For amateur radio operators, this ensures compatibility - everyone uses USB for these modes. Understanding this helps when operating these digital modes.
Exam Tip
JT65/JT9/FT4/FT8 with AFSK = USB. Think 'J'T/'F'T modes = 'U'pper 'S'ideband. These digital modes use USB on HF, similar to voice on higher HF bands. Not LSB (RTTY), not DSB - USB is standard for these modes.
Memory Aid
"JT65/JT9/FT4/FT8 with AFSK = USB. Think 'J'T/'F'T modes = 'U'pper 'S'ideband. These digital modes use USB on HF. Standard for JT65, JT9, FT4, and FT8 operation. Not LSB or DSB - USB."
Real-World Application
You operate FT8 on 20 meters using AFSK with an SSB transmitter. You use USB (Upper Sideband) - this is the standard for FT8, JT65, JT9, and FT4. Everyone uses USB for these modes, ensuring compatibility. LSB is used for RTTY, but these modes use USB.
Key Concepts
Why Other Options Are Wrong
Option A (LSB): Incorrect. LSB is used for RTTY and some other modes, but JT65, JT9, FT4, and FT8 use USB. USB is standard for these modes.
Option C (DSB): Incorrect. DSB (Double Sideband) isn't used for these modes - they use SSB (Single Sideband), specifically USB.
Option D (SSB): Incorrect. While these modes use SSB, the question asks which sideband - it's USB, not just 'SSB' in general.
题目解析
The correct answer is B: USB. The standard sideband for JT65, JT9, FT4, or FT8 digital signals when using AFSK is USB (Upper Sideband). These digital modes use USB on HF, similar to voice on higher HF bands. For amateur radio operators, this ensures compatibility - everyone uses USB for these modes. Understanding this helps when operating these digital modes.
考试技巧
JT65/JT9/FT4/FT8 with AFSK = USB. Think 'J'T/'F'T modes = 'U'pper 'S'ideband. These digital modes use USB on HF, similar to voice on higher HF bands. Not LSB (RTTY), not DSB - USB is standard for these modes.
记忆口诀
JT65/JT9/FT4/FT8 with AFSK = USB. Think 'J'T/'F'T modes = 'U'pper 'S'ideband. These digital modes use USB on HF. Standard for JT65, JT9, FT4, and FT8 operation. Not LSB or DSB - USB.
实际应用示例
You operate FT8 on 20 meters using AFSK with an SSB transmitter. You use USB (Upper Sideband) - this is the standard for FT8, JT65, JT9, and FT4. Everyone uses USB for these modes, ensuring compatibility. LSB is used for RTTY, but these modes use USB.
错误选项分析
Option A (LSB): Incorrect. LSB is used for RTTY and some other modes, but JT65, JT9, FT4, and FT8 use USB. USB is standard for these modes. Option C (DSB): Incorrect. DSB (Double Sideband) isn't used for these modes - they use SSB (Single Sideband), specifically USB. Option D (SSB): Incorrect. While these modes use SSB, the question asks which sideband - it's USB, not just 'SSB' in general.
知识点
JT65, JT9, FT4, FT8, USB, Digital modes
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.