Updated: Dec 9, 2025 | Source: 2023-2027 Question Pool | Topic: G2E
G2E05G2E

What is the standard sideband for JT65, JT9, FT4, or FT8 digital signal when using AFSK?

Deep Dive: G2E05

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.

Why Other Answers 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.

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 Example

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.

Source & Coverage

Question Pool: 2023-2027 Question Pool

Subelement: G2E

Reference: 2023-2027 Question Pool · G2 - Operating Procedures

Key Concepts

JT65 JT9 FT4 FT8 USB Digital modes

Verified Content

Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G2E topic.