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6
README
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@ -13,9 +13,9 @@
Copyright (C) 2001 - 2021 by Joe Taylor, K1JT.
WSJT-X Version 2.3 offers ten different protocols or modes: FT4, FT8,
JT4, JT9, JT65, Q65, FST4, MSK144, WSPR, FST4W, and Echo. The first
seven are designed for making reliable QSOs under weak-signal
WSJT-X Version 2.5 offers eleven different protocols or modes: FT4,
FT8, JT4, JT9, JT65, Q65, FST4, MSK144, WSPR, FST4W, and Echo. The
first seven are designed for making reliable QSOs under weak-signal
conditions. They use nearly identical message structure and source
encoding. JT65 and Q65 were designed for EME (“moonbounce”), but not
limited to just that propagation path, on the VHF/UHF bands and JT65

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@ -4,41 +4,50 @@ the program name stand for `(W)eak (S)ignal communication by K1(JT),`
while the suffix `-X` indicates that WSJT-X started as an extended and
experimental branch of the program WSJT.
.
WSJT-X Version 2.0 offers twelve different protocols or modes: FST4,
FST4W, FT4, FT8, JT4, JT9, JT65, QRA64, ISCAT, MSK144, WSPR, and Echo.
The first eight are designed for making reliable QSOs under extreme
weak-signal conditions. They use nearly identical message structure
and source encoding. 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. QRA64 has
a number of advantages over JT65, including better performance on the
very weakest signals. We imagine that over time it may replace JT65
for EME use. JT9 was originally designed for the LF, MF, and lower HF
bands. Its submode JT9A is 2 dB more sensitive than JT65 while using
less than 10% of the bandwidth. FST4, and its quasi-beacon companion
mode FST4W (see below), are designed for LF and MF and offer
significant advantages over JT9 and WSPR on those bands. JT4 offers a
wide variety of tone spacings and has proven highly effective for EME
on microwave bands up to 24 GHz. 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. FT8 is operationally similar but four times faster
(15-second T/R sequences) and less sensitive by a few dB. On the HF
bands, world-wide QSOs are possible with any of these modes using
power levels of a few watts (or even milliwatts) and compromise
antennas. On VHF bands and higher, QSOs are possible (by EME and
other propagation types) at signal levels 10 to 15 dB below those
required for CW.
WSJT-X Version 2.5 offers eleven different protocols or modes: FT4,
FT8, JT4, JT9, JT65, Q65, FST4, MSK144, WSPR, FST4W, and Echo. The
first seven are designed for making reliable QSOs under weak-signal
conditions. They use nearly identical message structure and source
encoding. JT65 and Q65 were designed for EME (“moonbounce”), but not
limited to just that propagation path, on the VHF/UHF bands and JT65
has also proven very effective for worldwide QRP communication on the
HF bands. Q65 has a number of advantages over JT65, including better
performance on the very weakest signals and variants with different
T/R period lengths. We imagine that over time it may replace JT65 for
EME use, it has also proved to be very effective for iono-scatter
paths on 6m. JT9 was originally designed for the LF, MF, and lower HF
bands. Its submode JT9A is 2 dB more sensitive than JT65 while using
less than 10% of the bandwidth. JT4 offers a wide variety of tone
spacings and has proven highly effective for EME on microwave bands up
to 24 GHz. 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. FT8 is operationally similar
but four times faster (15-second T/R sequences) and less sensitive by
a few dB. FT4 is faster still (7.5 s T/R sequences) and especially
well suited for radio contesting. On the HF bands, world-wide QSOs are
possible with any of these modes using power levels of a few watts (or
even milliwatts) and compromise antennas. QSOs are possible at signal
levels 10 to 15 dB below those required for CW. FST4 has similarities
in use to JT9 but offers more flexibility as it offers different
period lengths allowing QSO completion time to be traded off against
sensitivity. In its base form of FST4-60A it has better sensitivity
than JT9A and should be considered as an upgrade where JT9 has been
the preferred slow QSO mode.
.
ISCAT, MSK144, and optionally submodes JT9E-H are `fast` protocols
designed to take advantage of brief signal enhancements from ionized
meteor trails, aircraft scatter, and other types of scatter
Note that even though their T/R sequences are short, FT4 and FT8 are
classified as slow modes because their message frames are sent only
once per transmission. All fast modes in WSJT-X send their message
frames repeatedly, as many times as will fit into the Tx sequence
length.
.
MSK144, and optionally submodes JT9E-H are `fast` protocols designed
to take advantage of brief signal enhancements from ionized meteor
trails, aircraft scatter, and other types of scatter
propagation. These modes use timed sequences of 5, 10, 15, or 30 s
duration. User messages are transmitted repeatedly at high rate (up
to 250 characters per second, for MSK144) to make good use of the
shortest meteor-trail reflections or `pings`. ISCAT uses free-form
messages up to 28 characters long, while MSK144 uses the same
shortest meteor-trail reflections or `pings`. MSK144 uses the same
structured messages as the slow modes and optionally an abbreviated
format with hashed callsigns.
.
@ -54,6 +63,11 @@ archival storage, and many other features. WSPR has a new companion
FST4W which has a similar message content but offers up to 30 minute
transmission periods for greater sensitivity on LF and MF.
.
FST4W, like WSPR, is a quasi-beacon mode, it targets LF and MF bands
and offers a number of T/R periods form 2 minutes up to 30 minutes for
the most challenging weak signal paths. Similarly to WSPR reception
reports can be automatically uploaded to the WSPRnet.org web service.
.
Echo mode allows you to detect and measure your own station's echoes
from the moon, even if they are far below the audible threshold.
.