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"New in Version 2.5.0" added to the User Guide.

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Joe Taylor 2021-05-30 14:40:57 -04:00
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doc/user_guide/en/new_features.adoc
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[[NEW_FEATURES]]
=== New in Version {VERSION}
_WSJT-X 2.4.0_ introduces *Q65*, a new digital protocol designed for
minimal two-way QSOs over especially difficult propagation paths. On
paths with Doppler spread more than a few Hz, the weak-signal
performance of Q65 is the best among all WSJT-X modes.
_WSJT-X 2.5.0_ introduces an enhanced Q65 decoder that measures and
compensates for linear frequency drifts of Q65 signals. Activate this
feature by setting a spinner control *Max Drift* on the _WSJT-X_ main
window to a number greater than 0. We suggest a setting of 10 for
submode Q65-60A, the recommended submode for EME on 50 and 144 MHz,
which will accommodate drift rates up to 20 Hz/minute. Similarly, we
suggest *Max Drift* = 40 for submode Q65-15C, used for for 10 GHz QSOs
(up to 900 km) via aircraft scatter and drift rates up to about 20
Hz/s.
Q65 uses message formats and sequencing identical to those used in
FST4, FT4, FT8, and MSK144. Submodes are provided with a wide variety
of tone spacings and T/R sequence lengths 15, 30, 60, 120, and 300 s.
A new, highly reliable list-decoding technique is used for messages
that contain previously copied message fragments. Message averaging
is provided for situations where single transmissions are too weak or
signal enhancements too sparse for a signal to be decoded.
On the Windows platform only, _WSJT-X 2.5.0_ installations now include
an early version of _MAP65 3.0_. This program works together with
suitable hardware that converts RF to baseband. The hardware/software
combination implements a wideband, highly optimized receiver for the
Q65 and JT65 protocols, with matching transmitting features that
require a standard SSB transceiver. _MAP65_ is effective in both
single-polarization and dual-polarization systems. If two
polarization channels are available, _MAP65_ determines and matches
the linear polarization angle of each decodable signal. This
capability provides a major advantage for efficient EME communication
on bands up to 432 MHz. A single-channel _MAP65_ system works
extremely well for EME on 1296 MHz and higher bands, displaying all
signals in a 90 kHz sub-band and decoding all the Q65 and JT65
signals.