JS8Call – weak signal communication on HF with a keyboard-to-keyboard interface

And a related presentation on YouTube: https://www.youtube.com/watch?v=mZKhVcFOljY

"WSJT-X is a computer program designed to facilitate basic amateur radio communication using very weak signals.... JT65 and QRA64 were designed for EME (“moonbounce”) on the VHF/UHF bands and have also proven very effective for worldwide QRP communication on the HF bands.... JT9A is 2 dB more sensitive than JT65 while using less than 10% of the bandwidth.... These four “slow” modes use one-minute timed sequences of alternating transmission and reception, so a minimal QSO takes four to six minutes — two or three transmissions by each station, one sending in odd UTC minutes and the other even."

[0] from the WSJT-X 2.2 User Guide PDF (offers 10 languages) at: https://physics.princeton.edu/pulsar/k1jt/wsjtx.html