The author labled this mode as a 64-FSK modulation so this is why it is under FSK
QRA64 is an experimental mode intended for EME and other extreme weak-signal applications.
Its internal code was designed by IV3NWV.
The protocol uses a (63,12) Q-ary Repeat Accumulate code that is inherently better than the Reed Solomon (63,12) code used in JT65, yielding a 1.3 dB advantage.
A new synchronizing scheme is based on three 7 x 7 Costas arrays. This change yields another 1.9 dB advantage.
In most respects the current implementation of QRA64 is operationally similar to JT65.
QRA64 does not use two-tone shorthand messages, and it makes no use of a callsign database.
Rather, additional sensitivity is gained by making use of already known information as a QSO progresses - for example, when reports are being exchanged and you have already decoded both callsigns in a previous transmission.
QRA64 presently offers no message averaging capability, though that feature may be added. In early tests, many EME QSOs were made using submodes QRA64A-E on bands from 144
MHz to 24 GHz.
Modulation: 64-FSK
Bandwidth: 111.1 hz
TX duration: 48.4 secs.
Baud: 1.736
Min SNR:-26db based on 2500hz bandwidth noise
