How does Q65 differ from JT65?

Q65 is a digital protocol designed specifically for two-way communication over extremely difficult propagation paths, such as Earth-Moon-Earth (EME) or tropospheric scatter. A key distinction of Q65 compared to older modes like JT65 is its ability to average multiple receive cycles, allowing it to successfully decode signals that are deeply buried in the noise. Unlike traditional rag-chew modes, neither Q65 nor JT65 supports live keyboard-to-keyboard operation. Both are structured, time-synchronized protocols. Averaging successive transmissions provides the mathematical gain required for Q65 to achieve its remarkable weak-signal performance.