In 1998, Peter Martinez, G3PLX, introduced PSK31, a revolutionary digital mode for amateur radio communication. PSK31, which stands for Phase Shift Keying at a rate of 31.25 baud, was designed to facilitate efficient, low-bandwidth communication under weak signal conditions. This mode quickly gained popularity among amateur radio operators due to its robustness and effectiveness in making contacts using low power (QRP) and compromised antennas. PSK31’s narrow bandwidth of just 31.25 Hz allows multiple signals to coexist in a single sideband channel, promoting spectrum efficiency. Martinez’s innovation significantly enhanced the digital communication capabilities of amateur radio, fostering a global community of operators engaging in low-power digital communication.
