Ham Radio Extra Class Practice Test

In the context of digital modes used in ham radio, PSK31 is often recognized for its efficiency in bandwidth utilization. This mode operates at a baud rate of 31.25 baud and typically has a signal bandwidth close to 31.25 Hz. Given its modulation technique, which uses phase shift keying, PSK31 is designed to fit more effectively within tighter bandwidth constraints compared to other modes. When comparing the other options, MFSK16 has a wider bandwidth thanks to its use of multiple frequency shifts to carry data, resulting in a broader signal. On the other hand, 170 Hz shift, 45 baud RTTY, while it may appear narrow, typically requires a somewhat larger bandwidth due to its keying characteristics. The 300-baud packet mode also utilizes a greater bandwidth for effective data transmission. This makes PSK31 the choice with the narrowest bandwidth among the options provided, demonstrating its efficacy for operators wanting to maximize their usage of available spectrum space.