mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-18 10:01:57 -05:00
e690f453f8
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7401 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
106 lines
5.1 KiB
Plaintext
106 lines
5.1 KiB
Plaintext
Release: WSJT-X Version 1.7.0
|
|
-----------------------------
|
|
|
|
Short list of new features
|
|
--------------------------
|
|
1. New modes: ISCAT, MSK144, QRA64.
|
|
2. Newly implemented submodes: JT65B-C, JT9B-H (wide and fast).
|
|
3. FT decoder replaces KV decoder for JT65; KVASD is no longer used.
|
|
4. Improvements to JT4, JT9, and JT65 decoders.
|
|
5. Multi-pass decoding now implemented for JT65 as well as WSPR.
|
|
6. Many improvements to Rig Control.
|
|
7. Improved convenience features for EME Doppler tracking.
|
|
8. Multiple configurations can be saved and restored.
|
|
9. Sample-file download facility.
|
|
10. Optional auto-sequencing for Fast modes.
|
|
11. Power settings optionally remembered for Transmit and Tune on a
|
|
band-by-band basis.
|
|
|
|
New Modes
|
|
---------
|
|
|
|
1. MSK144 is intended for meteor scatter at 50 MHz and higher. It
|
|
uses a low-density parity check code (LDPC) designed by Steve Franke,
|
|
K9AN. The mode is a direct descendant of the now-defunct mode JTMSK,
|
|
with a number of improvements for better performance on weak and short
|
|
meteor pings. The effective character transmission rate is about 250
|
|
cps, compared with 147 cps for FSK441. Like JT4, JT9, JT65, and
|
|
QRA64, MSK144 uses strong forward error correction. Message decoding
|
|
is all or nothing: partial decodes do not occur, and you will see
|
|
little or no garbage on your screen.
|
|
|
|
Standard MSK144 message frames are 72 ms long, compared with about 120
|
|
ms for an equivalent FSK441 message. The MSK144 waveform allows
|
|
coherent demodulation, allowing up to 3 dB better sensitivity. After
|
|
QSO partners have exchanged callsigns, MSK144 can use even shorter
|
|
messages, only 20 ms long. As in all the fast modes in WSJT-X, the 72
|
|
ms (or 20 ms) messages are repeated without gaps for the duration of a
|
|
transmission cycle. For most purposes we recommend a T/R cycle
|
|
duration of 15 s, but 5 s and 10 s sequences are also supported.
|
|
|
|
Short ("Sh") messages in MSK144 are intended primarily for 144 MHz and
|
|
higher frequencies, where most pings are very short. These messages
|
|
do not contain full callsigns; instead, they contain a hash of the two
|
|
callsigns along with a report, acknowledgement, or 73. Short messages
|
|
are fully decodable only by the station to whom they are addressed, as
|
|
part of an ongoing QSO, because only then will the received hash match
|
|
that calculated using the known strings for "My Call" and "DX Call".
|
|
If you are monitoring someone else's QSO, you will not be able to
|
|
decode its Sh messages.
|
|
|
|
An MSK144 signal occupies the full bandwidth of a typical SSB
|
|
transmitter, so transmissions are always centered at an offset of
|
|
1500Hz. For best results, selectable or adjustable Rx and Tx filters
|
|
should be set to provide the flattest possible response over at least
|
|
300 - 2700 Hz. The maximum permissible frequency offset between you
|
|
and your QSO partner is 200 Hz, and less is better.
|
|
|
|
2. QRA64 is a intended for EME and other weak-signal use. Its
|
|
internal code was designed by Nico Palermo, IV3NWV, and implemented in
|
|
WSJT-X by K1JT. The protocol uses a "Q-ary Repeat Accumulate" code --
|
|
along with LDPC, another one of the latest research areas in
|
|
communication theory. The QRA64 code is inherently better than the
|
|
Reed Solomon (63,12) code used in JT65, yielding already a 1.3 dB
|
|
advantage. QRA64 uses a new synchronizing scheme based on a 7 x 7
|
|
Costas array, so you will not see a bright sync tone at the lowest
|
|
tone frequency. This change yields another 1.9 dB advantage.
|
|
|
|
In most respects our 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 may be
|
|
added. In our early tests, many EME QSOs have already been made using
|
|
submodes QRA64A-E on bands from 144 MHz to 10 GHz.
|
|
|
|
3. ISCAT is essentially the same as in recent versions of program WSJT.
|
|
For details consult the WSJT User Guide:
|
|
http://physics.princeton.edu/pulsar/K1JT/doc/wsjt/
|
|
|
|
|
|
Program Setup
|
|
-------------
|
|
|
|
Many of the new program capabilities are enabled when you check
|
|
"Enable VHF/UHF/Microwave features" on the Settings | General tab.
|
|
For MSK144 mode, we suggest setting "T/R 15 s" and "F Tol 100 Hz".
|
|
Check "Sh" to enable the use of short messages and "Auto Seq" for
|
|
auto-sequencing. For QRA64 mode, set Tx and Rx frequencies to 1000
|
|
Hz. We encourage you to check "Save all" when making tests, and to
|
|
save any of the resulting .wav files that might help us to improve
|
|
program performance or behavior, or to illustrate a problem that you
|
|
identify.
|
|
|
|
|
|
Final Comments
|
|
--------------
|
|
|
|
We will be grateful for any and all reports from users; these will
|
|
surely help us to make further improvements to WSJT-X. The most
|
|
helpful bug reports describe the problem clearly and include a
|
|
complete recipe to reproduce it. Feature requests are also welcome.
|
|
Send your reports to wsjtgroup@yahoogroups.com, or to the developers
|
|
list wsjt-devel@lists.sourceforge.net.
|