Ham Amateur Radio Technician Practice Exam

Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?

1. PSK31

2. FT8

3. WSPR

4. Psk63

The correct answer is: FT8

FT8 is a narrow-band digital mode specifically designed for weak signal communication and performs exceptionally well in low signal-to-noise ratio conditions. It uses advanced error correction and encoding techniques, allowing operators to decode signals even when they are barely above the noise floor. FT8 transmits data in short bursts, which is effective in capturing brief signals and minimizing the effects of noise. This mode's design enables it to make connections under challenging conditions, such as during poor propagation or when interference is present, thereby allowing amateur radio operators to communicate effectively even when conditions are less than ideal. While other modes like PSK31 and WSPR also have their own strengths, FT8's efficiency and robustness against noise make it particularly effective for receiving faint signals, which aligns with the requirement outlined in the question.