More work on User Guide, section 6.

This commit is contained in:
Steven Franke 2021-07-27 17:41:02 -05:00
parent 01990baa58
commit 06fee9c52a
4 changed files with 105 additions and 19 deletions

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@ -7,16 +7,86 @@
.Open a Wave File:
- Select *File | Open* and navigate to
+...\save\samples\FT8\181201_180245.wav+. The waterfall and Band
Activity window should look something like the following screen shots.
(This recording was made during the "FT8 Roundup" contest, so most
transmissions happen to be using *RTTY Roundup* message formats.)
+...\save\samples\FT8\210703_133430.wav+. The waterfall and Band
Activity window should look something like the following screen shots:
- You may want to pretend you are K1JT
by entering that callsign temporarily as *My Call* on the
*Settings | General* tab. Your results should then be identical to
those shown in the screen shot below. Don't forget to change *My Call*
back to your own call when you are done!
[[X15]]
image::FT8_waterfall.png[align="left",alt="Wide Graph Decode 170709_135615"]
image::FT8_waterfall.png[align="left",alt="Wide Graph Decode 210703_133430"]
image::ft8_decodes.png[align="left"]
.Decoding Overview
Decoding takes place at the end of a receive sequence. With *Decode* set
to *Deep*, three decoding passes will be done. The *Decode* button on the
mainwindow will illuminate three times, once for each pass.
The first decoding attempt in each decoding pass is done at the selected Rx frequency,
indicated by the U-shaped green marker on the waterfall frequency
scale. Results appear in both the left (*Band Activity*) and right
(*Rx Frequency*) text windows on the main screen. The program then
finds and decodes all signals in the selected mode over the displayed
frequency range. The red marker on the waterfall scale indicates your
Tx frequency.
Twenty one FT8 signals are decoded from the example file. The number
of decodes is shown at the bottom of the main window.
When this file was recorded HA5WA was finishing a QSO with K1JT and
his 73 message is shown in red because it is addressed to *My Call* (in this case K1JT).
The *Band Activity* window shows this message along with
all decodes at other frequencies. By default, lines containing `CQ`
are highlighted in green, and lines with *My Call* (K1JT)
in red. Notice that K1JT has two callers; HA0DU and EA3AGB.
[[X13]]
.Decoding Controls
To gain some feeling for controls frequently used when making QSOs,
try double-clicking with the mouse on the decoded text lines and on the
waterfall spectral display. You should be able to confirm the
following behavior:
- Double-click on one of the decoded lines highlighted in
green. These actions produce the following results:
** Callsign and locator of a station calling CQ are copied to the *DX
Call* and *DX Grid* entry fields.
** Messages are generated for a standard minimal QSO.
** The *Tx even* box is checked or cleared appropriately, so that you
will transmit in the proper (odd or even) minutes.
** The Rx frequency marker is moved to the frequency of the CQing
station.
** You can modify the double-click behavior by holding down the
*Shift* key to move only the Tx frequency or the *Ctrl* key to move
both Rx and Tx frequencies.
** In addition, if *Double-click on call sets Tx enable* is checked on the
*Settings | General* tab then *Enable Tx* will be activated
so that a transmission will start automatically at the proper time.
+
NOTE: You can prevent your Tx frequency from being changed by checking the
box *Hold Tx Freq*.
- Double-click on the decoded message `K1JT HA0DU KN07`, highlighted
in red. Results will be similar to those in the previous step. The Tx
frequency (red marker) is not moved unless *Shift* or *Ctrl* is held
down. Messages highlighted in red are usually in response to your own
CQ or from a tail-ender, and you probably want your Tx frequency to
stay where it was.
- Click with the mouse anywhere on the waterfall display. The green Rx
frequency marker will jump to your selected frequency, and the Rx
frequency control on the main window will be updated accordingly.
@ -33,11 +103,12 @@ things just described and also invokes the decoder in a small range
around the Rx frequency. To decode a particular signal, double-click
near the left edge of its waterfall trace.
- Now double-click on any of the lines of decoded text in the Band
Activity window. Any line will show the same behavior, setting
Rx frequency to that of the selected message and leaving Tx frequency
unchanged. To change both Rx and Tx frequencies, hold *Ctrl* down
when double-clicking.
- Ctrl-double-click on a signal to set both Rx and Tx frequencies and
decode at the new frequency.
- Click *Erase* to clear the right window.
- Double-click *Erase* to clear both text windows.
TIP: To avoid QRM from competing callers, it is usually best
to answer a CQ on a different frequency from that of the CQing

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// Status=review
Set up the Wide Graph (also called the Waterfall). It is important to set appropriate lower and upper
audio frequency limits for the Wide Graph because these limits define the FT8 decoder's search window.
Set up the Wide Graph (also called the Waterfall).
It is important to set appropriate lower and upper
audio frequency limits for the Wide Graph because these limits define the FT8 decoder's search window:
- Set *Start* = 100 Hz.
- Set *Bins/Pixel* = 5. Smaller/larger values make the Wide Graph cover a smaller/larger
frequency range.
- Use the mouse to grab the left or right edge of the *Wide Graph*, and
adjust its width so that the upper frequency limit is about 3300 Hz.
- Set *N Avg* = 2. Smaller/larger values will make the wide graph update more/less frequently, resulting
in signals being more/less spread out in the vertical (time) direction on the Wide Graph spectrogram.
Larger values make it easier to see very weak signals.
- *Palette* = Digipan
The *N Avg* setting controls how many spectra are averaged to produce each line in the spectrogram.
Smaller values make the spectrogram update more frequently, resulting in signals being more spread
out in the vertical (time) direction.
On the other hand, larger values make it easier to detect very weak signals:
- Set *N Avg* = 2.
The *Palette* setting controls the color scheme used for the spectrogram:
- Set *Palette* = Fldigi
When *Flatten* is checked, WSJT-X attempts to correct for rolloff at the lowest and highest
frequencies in the spectrum:
- *Flatten* = checked
- Select *Cumulative* for data display
- *Gain* and *Zero* sliders for waterfall and spectrum set near midscale
- Set *Spec* = 25%. This value determines the percentage of the vertical size of the Wide Graph
that will be used for the line plot of the spectrum.
- Set the *Gain* and *Zero* sliders for the waterfall and spectrum to near midscale
The *Spec* setting determines what fraction of the vertical extent of the Wide Graph will
be used for the line plot of the spectrum. Setting *Spec* to 0 will eliminate the line plot.
- Set *Spec* = 25%