Add a section on EME Tips to the User Guide.

This commit is contained in:
Joe Taylor 2020-05-08 10:02:05 -04:00
parent 101356c26c
commit 3a7eda58ea
7 changed files with 98 additions and 13 deletions

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@ -74,6 +74,9 @@ set (UG_IMGS
images/decodes.png
images/download_samples.png
images/echo_144.png
images/EME_Deep_0.png
images/EME_Deep_1.png
images/EME_Deep_2.png
images/file-menu.png
images/FreqCal.png
images/FreqCal_Graph.png

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@ -1,3 +1,4 @@
[[AP_Decoding]]
=== AP Decoding
The _WSJT-X_ decoders for FT4, FT8, JT65, and QRA64 include optional
@ -92,6 +93,7 @@ averaged to obtain the decode.
|===========================================
[[Decoded_Lines]]
=== Decoded Lines
Displayed information accompanying decoded messages generally includes UTC,
@ -109,10 +111,10 @@ summarized in the following Table:
|===========================================
|Mode |Mode character|Sync character|End of line information
|FT8 | ~ | | ?   aP
|JT4 | $ | *, # | f, fN, dNC
|JT4 | $ | *, # | f, fN, dCN
|JT9 | @ | |
|JT65 | # | |
|JT65 VHF| # | *, # | f, fN, dNC
|JT65 VHF| # | *, # | f, fN, dCN
|QRA64 | : | * | R
|ISCAT | | * | M N C T
|MSK144 | & | | N H E

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@ -4,11 +4,10 @@ _WSJT-X_ is a computer program designed to facilitate basic amateur
radio communication using very weak signals. The first four letters in
the program name stand for "`**W**eak **S**ignal communication by
K1**JT**,`" while the suffix "`-X`" indicates that _WSJT-X_ started as
an e**Xt**ended (and originally e**X**perimental) branch of the
program _WSJT_.
Bill Somerville, G4WJS, and Steve Franke, K9AN, have been major
contibutors to program development since 2013 and 2015, respectively.
an e**Xt**ended and e**X**perimental branch of the program _WSJT_,
first released in 2001. Bill Somerville, G4WJS, and Steve Franke,
K9AN, have been major contibutors to program development since 2013
and 2015, respectively.
_WSJT-X_ Version {VERSION_MAJOR}.{VERSION_MINOR} offers ten different
protocols or modes: *FT4*, *FT8*, *JT4*, *JT9*, *JT65*, *QRA64*,

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@ -335,10 +335,91 @@ of the plot area on the Echo Graph window.
image::echo_144.png[align="center",alt="Echo 144 MHz"]
=== VHF+ Sample Files
=== Tips for EME
Sample recordings typical of QSOs using the VHF/UHF/Microwave modes
and features of _WSJT-X_ are available for
<<DOWNLOAD_SAMPLES,download>>. New users of the VHF-and-up features
are strongly encouraged to practice decoding the signals in these
files.
The following tutorial aims to familiarize you with program features
of particular interest for EME and other extreme weak-signal
conditions. As a starting point, configure _WSJT-X_ as follows:
.Settings | General:
- *My Call* = W9XYZ
- Check these boxes: *Enable VHF/UHF/Microwave features*, *Single
decode*, *Decode after EME delay*
.Settings | Advanced:
- *Random erasure patterns* = 7, *Aggressive decoding level* = 0,
*Two-pass decoding* = _unchecked_, *Waterfall spectra* = _Most sensitive_
.Main window menus:
- *View* = Message averaging
- *Mode* = JT65
- *Decode:* *Deep* selected, *Enable averaging* checked,
*Enable deep search* unchecked, *Enable AP* checked
.Main window:
- *F Tol* = 500, *Rx* 1500 *Hz*, *Submode* = B, *Sync* = 0
- *DX Call*, *DX Grid:* both empty
.Wide Graph:
- *Bins/Pixel* = 3, *N Avg* = 10
- Adjust the width of the window so that the frequency range extends
up to at least 2400 Hz.
If you have not already done so, install the sample files available
for <<DOWNLOAD_SAMPLES,download>>. Select *File | Open* and navigate
to ...\save\samples\JT65\JT65B\000000_0001.wav.
The waterfall should look something like the snapshot below. A barely
visible vertical trace appears at 1300 Hz. This is the synchronizing
tone of a simulated JT65B signal with SNR = -26 dB.
image::EME_Deep_0.png[align="center",alt="EME_Deep_0"]
The decoder recognizes the sync tone of a JT65 signal, but is unable
to decode it, producing only this line in the _Single Period Decodes_
panel:
0001 -28 2.5 1300 #*
Press *F6* repeatedly, to read subsequent files. When
five files have been read your display should look like this:
image::EME_Deep_1.png[align="center",alt="EME_Deep_1"]
The message `CQ K1ABC FN42` appears in the _Average Decodes_ panel,
flagged with the <<Decoded_Lines,end-of line label>> `f3`. The label
means that decoding was accomplished with the Franke-Taylor
algorithm, using the average or 3 transmissions.
The _Message Averaging_ window now looks like this:
image::EME_Deep_2.png[align="center",alt="EME_Deep_2"]
The `$` symbols mark lines corresponding to transmissions used in the
most recent attempt toward an average decode.
Hit the *F6* key again to read the sixth file. You should now see the
message `K1ABC G4XYZ IO91` displayed in the _Average Decodes_ panel,
again with the `f3` label.
Now pretend you are K1ABC (enter `K1ABC` and `FN42` as *My Call* and
*My Grid* on the *Settings | General* tab). Click *Clear Avg* and
double-click *Erase* to start with a fresh screen. Open the files
000000_0002.wav and 000000_0004.wav. You should now see the message
`K1ABC G4XYZ IO91` in the _Average Decodes_ panel. Its end-of-line
flag `a22` indicates that this decode used *My Call* as _a priori_
(AP) information of type 2 (see Table 1 in <<AP_Decoding,AP
Decoding>>), and is based on the average of 2 transmissions.
You might wish to experiment with other combinations of entries for
*My Call*, *DX Call*, and *DX Grid*, and with toggling the various
options of the *Decode* menu on and off.