What does an FT8 signal report of +3 mean?
The correct answer is C: The signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth. What an FT8 signal report of +3 means is that the signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth. FT8 reports are in dB relative to noise in a 2.5 kHz bandwidth. For amateur radio operators, this is how FT8 signal reports work. Understanding this helps when operating FT8.
Exam Tip
FT8 report +3 = signal-to-noise ratio equivalent to +3dB in 2.5 kHz bandwidth. Think 'F'T8 'R'eport = 'F'requency 'T'one '8' = 'R'eport in 'd'B relative to noise. FT8 reports are in dB relative to noise in 2.5 kHz bandwidth. Not 3× noise, not S3, not S9+3 - just +3dB SNR in 2.5 kHz.
Memory Aid
"FT8 report +3 = signal-to-noise ratio equivalent to +3dB in 2.5 kHz bandwidth. Think 'F'T8 'R'eport = 'd'B relative to noise. FT8 reports are in dB relative to noise in 2.5 kHz bandwidth. Standard FT8 reporting format."
Real-World Application
An FT8 signal report of +3: The signal-to-noise ratio is equivalent to +3 dB in a 2.5 kHz bandwidth. This means the signal is 3 dB above the noise floor in that bandwidth. FT8 reports are standardized - they're always relative to noise in a 2.5 kHz bandwidth. This is how FT8 signal reports work.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. +3 doesn't mean 3 times noise level - FT8 reports are in dB, not multiples. 3× noise would be about +4.8 dB, not +3 dB.
Option B: Incorrect. +3 doesn't mean S3 - FT8 reports are in dB relative to noise, not S-meter readings. S3 is different.
Option D: Incorrect. +3 doesn't mean 3 dB over S9 - FT8 reports are relative to noise, not S-meter. S9+3 dB is different.
题目解析
The correct answer is C: The signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth. What an FT8 signal report of +3 means is that the signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth. FT8 reports are in dB relative to noise in a 2.5 kHz bandwidth. For amateur radio operators, this is how FT8 signal reports work. Understanding this helps when operating FT8.
考试技巧
FT8 report +3 = signal-to-noise ratio equivalent to +3dB in 2.5 kHz bandwidth. Think 'F'T8 'R'eport = 'F'requency 'T'one '8' = 'R'eport in 'd'B relative to noise. FT8 reports are in dB relative to noise in 2.5 kHz bandwidth. Not 3× noise, not S3, not S9+3 - just +3dB SNR in 2.5 kHz.
记忆口诀
FT8 report +3 = signal-to-noise ratio equivalent to +3dB in 2.5 kHz bandwidth. Think 'F'T8 'R'eport = 'd'B relative to noise. FT8 reports are in dB relative to noise in 2.5 kHz bandwidth. Standard FT8 reporting format.
实际应用示例
An FT8 signal report of +3: The signal-to-noise ratio is equivalent to +3 dB in a 2.5 kHz bandwidth. This means the signal is 3 dB above the noise floor in that bandwidth. FT8 reports are standardized - they're always relative to noise in a 2.5 kHz bandwidth. This is how FT8 signal reports work.
错误选项分析
Option A: Incorrect. +3 doesn't mean 3 times noise level - FT8 reports are in dB, not multiples. 3× noise would be about +4.8 dB, not +3 dB. Option B: Incorrect. +3 doesn't mean S3 - FT8 reports are in dB relative to noise, not S-meter readings. S3 is different. Option D: Incorrect. +3 doesn't mean 3 dB over S9 - FT8 reports are relative to noise, not S-meter. S9+3 dB is different.
知识点
FT8 signal report, +3 dB, Signal-to-noise ratio, 2.5 kHz bandwidth
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.