File: vhf-features.adoc

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_WSJT-X_ supports a number of modes and features designed for use on
the VHF and higher bands:

- *FT4*, for contesting

- *FT8*, for fast QSOs with weak, fading signals

- *JT4*, for EME on the microwave bands

- *JT9 fast modes*, for scatter propagation on VHF bands

- *JT65*, for EME on VHF and higher bands

- *Q65*, for ionospheric scatter, tropospheric scatter, rain scatter, 
TEP, and EME

- *MSK144*, for meteor scatter

- *Doppler tracking*, which is especially important for EME on bands
1.2 GHz and higher.

- *Echo* mode, for detecting and measuring your own lunar echoes

[[VHF_SETUP]]
=== VHF Setup

To activate the VHF-and-up features:

- On the *File | Settings | General* tab check *Enable VHF and submode
features*.

- For EME, check *Decode after EME delay* to allow for the path
delay on received lunar echoes.

- If you will use automatic Doppler tracking and your radio accepts
frequency-setting commands while transmitting, check *Allow Tx
frequency changes while transmitting*.  Transceivers known to permit
such changes include the IC-735, IC-756 Pro II, IC-910-H, IC-9700,
FT-847, TS-590S, TS-590SG, TS-2000 (with Rev 9 or later firmware
upgrade), Flex 1500 and 5000, HPSDR, Anan-10, Anan-100, and KX3.  To
gain full benefit of Doppler tracking your radio should allow
CAT-controlled frequency changes in 1 Hz steps.

NOTE: If your radio does not accept commands to change frequency
while transmitting, Doppler tracking will be approximated with a
single Tx frequency adjustment before a transmission starts, using a
value computed for the middle of the Tx period.

- On the *Radio* tab select *Split Operation* (use *Rig* or *Fake
It*. You may need to experiment with both options to find the one that
works best with your radio). *Fake it* is provided to allow the
necessary changes in receive and transmit frequencies for rigs that
have only one VFO accessible via CAT. It accomplishes this by sending
the required transmit frequency shortly before the start of the
transmit period.  Functionally there is no difference in operation of
*Rig* or *Fake it*, except possibly for timing details.

image::Split_settings.png[align="center",alt="Split Settings"]

Successful setting of split operation can be verified by checking that 
S is embedded in the indicator between the band combo box and the dial frequency
indicator. In some circumstances the S may only appear after a frequency or 
band change.  If the S is not present, Doppler correction will not function.

image::letter-s.png[align="center",alt="Split Settings"]

- On the right side of the lower main window select *Tab 1* to present
the traditional format for entering and choosing Tx messages.  The
main window will reconfigure itself as necessary to display controls
supporting the features of each mode.

- If you are using a transverter, set the appropriate frequency offset
on the *File | Settings | Frequencies* tab.  Offset is defined as
(transceiver dial reading) minus (on-the-air frequency).  For example,
when using a 144 MHz radio at 10368 MHz, *Offset (MHz)* = (144 -
10368) = -10224.  If the band is already in the table, you can edit
the offset by double clicking on the offset field.  Otherwise a new
band can be added by right clicking in the table and selecting
*Insert*.

image::Add_station_info.png[align="center",alt="Station information"]

- On the *View* menu, select *Astronomical data* to display a window
with important information for tracking the Moon and performing
automatic Doppler control.  The right-hand portion of the window
becomes visible when you check *Doppler tracking*.

image::Astronomical_data.png[align="center",alt="Astronomical data"]

Five different types of Doppler tracking are provided:

- Select *Full Doppler to DX Grid* if you know your QSO partner's locator
and he/she will not be using any Doppler control.

- Select *Own Echo* to enable EME Doppler tracking of your receive
frequency to your own echo frequency. Your Tx frequency will remain fixed
and is set to the Sked frequency.  This mode can be used when announcing 
your CQ call on a specific frequency and listening on your own echo
frequency.  It can also be used for echo testing with Echo mode.

- Select *Constant frequency on Moon (CFOM)* to correct for your own one-way
Doppler shift to or from the Moon.  If your QSO partner does the same
thing, both stations will have the required Doppler compensation.
Moreover, anyone else using this option will hear both of you
without the need for manual frequency changes.

- Select *On Dx Echo* when your QSO partner announces his/her transmit
frequency and that they are listening on their own echo
frequency. When clicked, this Doppler method will set your rig
frequency on receive to correct for the mutual Doppler shift. On
transmit, your rig frequency will be set so that your QSO partner will
receive you on the same frequency as they receive their own echo.
Sked frequency in this case is set to that announced by your QSO
partner.

- Select *Call DX* after tuning the radio manually to find a station,
with the Doppler mode initially set to *None*. You may be tuning the band
looking for random stations, or to a frequency where a station has been
seen on an SDR display.  It is usually necessary to hold down the Ctrl key
while tuning the radio. From the moment *Call DX* is pressed, your 
transmit frequency is set so that your echo will fall on the same 
frequency you (and the DX station) are listening. 

NOTE: All the above Doppler methods assume that RIT in the receiver is
set to zero.

- See <<ASTRODATA,Astronomical Data>> for details on the quantities
displayed in this window.

=== JT4

JT4 is designed especially for EME on the microwave bands, 2.3 GHz and
above.

- Select *JT4* from the *Mode* menu.  The central part of the main
window will look something like this:

image::VHF_controls.png[align="center",alt="VHF Controls"]

- Select the desired *Submode*, which determines the spacing of
transmitted tones. Wider spacings are used on the higher microwave
bands to allow for larger Doppler spreads. For example, submode JT4F
is generally used for EME on the 5.7 and 10 GHz bands.

- For EME QSOs some operators use short-form JT4 messages consisting
of a single tone.  To activate automatic generation of these messages,
check the box labeled *Sh*. This also enables the generation of a
single tone at 1000Hz by selecting Tx6, to assist in finding signals
initially.  The box labeled *Tx6* toggles the Tx6 message from 1000Hz
to 1250Hz to indicate to the other station that you are ready to
receive messages.

- Select *Deep* from the *Decode* menu.  You may also choose to
*Enable averaging* over successive transmissions and/or *Enable deep
search* (correlation decoding).

image::decode-menu.png[align="center",alt="Decode Menu"]

The following screen shot shows one transmission from a 10 GHz EME
QSO using submode JT4F.

image::JT4F.png[align="center",alt="JT4F"]

[[VHF_JT65]]
=== JT65

In many ways JT65 operation on VHF and higher bands is similar to HF
usage, but a few important differences should be noted.  Typical
VHF/UHF operation involves only a single signal (or perhaps two or
three) in the receiver passband.  We recommend that you check *Single
decode* on the *Settings | General* tab, and do not check *Two pass
decoding* on the *Advanced* tab.  With VHF features enabled the JT65
decoder will respond to special message formats often used for EME:
the OOO signal report and two-tone shorthand messages for RO, RRR, and
73.  These messages are always enabled for reception; they will be
automatically generated for transmission if you check the shorthand
message box *Sh*.  *Deep* on the *Decode* menu will be automatically
selected.  You may optionally include *Enable averaging*, *Enable Deep
search*, *Enable AP*, and *Auto Clear Avg after decode*.

The following screen shot shows three transmissions from a 144 MHz EME
QSO using submode JT65B and shorthand messages.  Take note of the
colored tick marks on the Wide Graph frequency scale.  The green
marker at 1220 Hz indicates the selected QSO frequency (the frequency
of the JT65 Sync tone) and the *F Tol* range.  A green tick at 1575 Hz
marks the frequency of the highest JT65 data tone.  Orange markers
indicate the frequency of the upper tone of the two-tone signals for
RO, RRR, and 73.

image::JT65B.png[align="center",alt="JT65B"]

=== Q65

Q65 is designed for fast-fading signals: EME, tropospheric scatter,
rain scatter, ionospheric scatter, trans-equatorial propagation (TEP),
and the like.  The following screen shot shows the Wide Graph and
decoded text windows after processing a Q65-60A sequence received via
EME on 6 meters, by W7GJ Transmissions are decoded from N0TB, N8JX,
W1VD, and VE1JF, all by the EME path.

image::Q65-60A_EME_6m.png[align="center"]

The Q65 decoder takes advantage of _a priori_ (AP) information such as
the encoded forms of one's own callsign and the message word `CQ`.  In
normal usage, as a QSO progresses AP information increases to include
the callsign of the station being worked and perhaps his/her 4-digit
grid locator.  The decoder takes advantage of whatever AP information
is currently available.

Here's a similar screen shot for a 6 m ionospheric scatter signal over
the 1155 km path from K9AN to K1JT, using submode Q65-30A. The
received signal was barely audible most of the time.

image::Q65_6m_ionoscatter.png[align="center",alt="Q65"]

For Q65 EME QSOs on the microwave bands, some operators
use short-form messages consisting of a single tone.  To activate
automatic generation of these messages, check the box labeled *Sh*.
This also enables the generation of a single tone at 1000Hz by
selecting Tx6, to assist in finding signals initially.  The box
labeled *Tx6* switches the Tx6 message from 1000Hz to 1250Hz to
indicate to the other station that you are ready to receive messages.
These short-form messages are not decoded automatically, and
auto-sequencing will not respond to them.  You must recognize and
interpret them yourself.

=== MSK144

Meteor scatter QSOs can be made any time on the VHF bands at distances
up to about 2100 km (1300 miles). Completing a QSO takes longer in the
evening than in the morning, longer at higher frequencies, and longer
at distances close to the upper limit. But with patience, 100 W or
more, and a single yagi it can usually be done, even on bands as high
as 432 MHz. The following screen shot shows two 15-second reception
intervals containing MSK144 signals from three different stations.

image::MSK144.png[align="center",alt="MSK144"]

Unlike other _WSJT-X_ modes, the MSK144 decoder operates in real time
during the reception sequence.  Decoded messages will appear on your
screen almost as soon as you hear them.

To configure _WSJT-X_ for MSK144 operation:

- Select *MSK144* from the *Mode* menu.

- Select *Fast* from the *Decode* menu.

- Set the audio receiving frequency to *Rx 1500 Hz*.

- Set frequency tolerance to *F Tol 100*.

- Set the *T/R* sequence duration to 15 s or 30s according to local standards.

- To match decoding depth to your computer's capability, click
*Monitor* (if it's not already green) to start a receiving sequence.
Observe the percentage figure displayed on the _Receiving_ label in
the Status Bar:

image::Rx_pct_MSK144.png[align="center",alt="MSK144 Percent CPU"]

- The displayed number (here 17%) indicates the fraction of available
time being used for execution of the MSK144 real-time decoder.  If
this number is well below 100%, you may increase the decoding depth
from *Fast* to *Normal* or *Deep*, and increase *F Tol* from 100 to
200 Hz. Most modern multi-core computers can easily handle the optimum
parameters *Deep* and *F Tol 200*.

- T/R sequences of 15 seconds or less requires selecting your
transmitted messages very quickly.  Check *Auto Seq* to have the
computer make the necessary decisions automatically, based on the
messages received.

- For operation at 144 MHz or above you may find it helpful to use
short-format *Sh* messages for Tx3, Tx4, and Tx5.  These messages are
20 ms long, compared with 72 ms for full-length MSK144 messages.
Their information content is a 12-bit hash of the two callsigns,
rather than the callsigns themselves, plus a 4-bit numerical report,
RRR, or 73.  Only the intended recipient can decode short-messages.
They will be displayed with the callsigns enclosed in <> angle
brackets, as in the following model QSO

 CQ K1ABC FN42
                    K1ABC W9XYZ EN37
 W9XYZ K1ABC +02
                    <K1ABC W9XYZ> R+03
 <W9XYZ K1ABC> RRR
                    <K1ABC W9XYZ> 73

+

NOTE: There is little or no advantage to using MSK144 *Sh*
messages at 50 or 70 MHz.  At these frequencies, most pings are long
enough to support standard messages -- which have the advantage of
being readable by anyone listening in.

[[OFFSET_CQ]]
.Offset CQ

The use of this feature is recommended when the calling channel is busy, 
as it allows QSOs to be conducted on a frequency of your choice free of QRM.
For example, if you wish to call CQ on 144.360MHz and conduct your QSO on 144.388MHz,
follow the steps below:

- Tune your radio to 144.388MHz

- Click the checkbox to the right of the *Tx CQ nnn* control, as shown below.

- Use the spinner in this control to set a value of 360.  Values between 010 and 999 
are accepted.

Your CQ message in *Tx6* containing your offset frequency will then be transmitted 
at 144.360, and your radio will be set to 144.388MHz on receive when your CQ call completes.
Subsequent QSO messages will be transmitted on 144.388MHz.

image::CQoffset_cb.png[align="center",alt="CQoffset_cb"]


On reception, when you double-click on a
message like `CQ nnn K1ABC FN42` your rig will QSY to the specified QSO frequency.
Thr QSO will then take place on that frequency.

NOTE: These features are available in the fast JT9 submodes as
well as MSK144. For them to work you must have a CAT controlled radio 
and *Split operation* activated on the *File | Settings | Radio* tab.

- Normally WSJT-X will send only one 73 message. When copy is marginal
and repeat transmissions often required, it may be desirable to send
more than one. Check the box *MSK144/Q65: Tx until 73 is received* in
the *File | Settings | General* Behavior group. A maximum of ten
attempts will be made before it times out if a 73 message has not yet
been received. You can use *Wait & Reply* in case this is still
not enough.

=== Echo Mode

*Echo* mode provides tools for two types of measurements: lunar echoes
of your own transmitted signal, and broadband noise power received
from the Sun, Moon, and other sources including ambient-temperature
ground and nearby objects. Such measurements are widely used for
optimizing a station's capabilities for Earth-Moon-Earth (EME)
communication. In addition, you can generate lunar echoes of short
alphanumeric messages for demonstration and amusement purposes.

For quantitative measurements the Echo-mode transmission is a
fixed-frequency 1500 Hz tone lasting 2.048 s. After sending it
_WSJT-X_ switches back to receive, records the lunar echo about 2.5 s
later, computes its spectrum, and displays results. The program takes
care of necessary T/R switching and frequency adjustments for Doppler
compensation. To make such measurements, be sure to check *Enable VHF
and submode features* on the *File | Settings | General* tab.  Set
*Split Operation* to *Rig* or *Fake It* on the *Settings | Radio* tab,
*Doppler tracking* and *Own Echo* or *Constant frequency on Moon* on
the *Astronomical Data* window.

.Fixed Tone Echoes

Select *Fixed Tone* on the main window, point your antenna at the
Moon, and click *Enable Tx* to start a sequence of measurements.  Each
Echo-mode cycle takes 6 seconds. The average echo spectrum will be
displayed in the *Echo Graph* window, and measurements appear in the
main window. If echoes are strong enough they will be visible in the
waterfall, centered at 1500 Hz. A spinner control labeled *Avg* (to
the left of the *Decode* button) controls averaging of successive Echo
sequences. Displayed SNR and the plotted Echo spectrum will be
averaged over the selected number of sequences.

image::Echo_1296.png[align="center",alt="Echo 144 MHz"]

Each echo cycle produces a line of data in the main window with the
following information:

 UTC       Time in hhmmss format
 Hour      UTC in hours and decimal fraction
 Level     Relative received noise power (dB)
 Doppler   EME Doppler shift at center of lunar disk
 Width     EME Doppler spread over full lunar disk
 N         Number of accumulated echo or monitor cycles
 Q         Estimated quality of averaged data on a 0 – 10 scale
 DF        Offset of spectral peak from 1500 Hz
 SNR       Average signal-to-noise ratio (dB/2500 Hz)
 dBerr     Estimated uncertainty of SNR

.MFSK Echoes

In addition to the traditional Echo mode, for amusement you can
transmit short messages (up to six alphanumeric characters) and
receive their echoes, using either multi-tone frequency-shift keying
or standard Morse code.  For the former, select *MFSK*, set a suitable
tone spacing at least one-third of the expected Doppler spread, and
enter your callsign in the field provided. If your radio's dial
frequency is controlled in 10 Hz steps, use tone spacing of at least
20 Hz.

image::Echo_controls.png[align="center",alt="Echo controls"]

After you click *Enable Tx*, _WSJT-X_ will send a sequence of six
tones, each lasting 0.341 s, to convey the characters in the entry
field. Message encoding is trivial, with no forward error correction:
each tone has a frequency offset from 1500 Hz corresponding to the
position of that character in the sequence
0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ. Lines displayed in the main text
window will then include three additional items:

 DT        Timing offset (s), for diagnostic purposes
 TS        Tone spacing (Hz)
 EchoMsg   Decoded MFSK message
 
Note that when *MFSK* is selected and *Avg* is set to anything larger
than 1, the decoded echo message will be averaged indefinitely, until
you click *Clear Avg*.

Here's an example of *MFSK* echo testing at 10 GHz, from DL3WDG. You
can easily see the five distinct callsign characters 3 D G L W (in
order of increasing tone frequency) in the waterfall. The spectrum
plotted in the *Echo Graph* window is the average of all six tones,
with their individual frequency offsets removed. The full width of the
echo signal near the baseline is very close to the predicted value, 66
Hz.

image::Echo_10GHz.png[align="center",alt="Echo 10 GHz"]

.CW Echoes

Select *CW* to send a short message by Morse code, repeated with the
usual 6 s Echo cycle. If you can hear your own echoes, this feature is
especially good for demonstration purposes. Code speed will be
automatically adjusted so the message just fits into the allotted
2.048 s Tx interval. The most useful CW messages will be short and
simple, such as “O” or “OO”.

System timing details are important. Echo-mode features work best when
the station's T/R switch-over times are no longer than a few hundred
milliseconds in each direction. In most amateur EME setups these times
are determined by programmed software delays, response time of a 
CAT-controlled transceiver, and any hardware sequencers in use.

Most Echo-mode features require Doppler compensation via CAT control
of your radio. You may find it important to experiment with software
options that affect system timing. Use the radio’s Monitor function
(or listen on another receiver) to make sure that in *MFSK* mode you
transmit all six tones at their full programmed length. Try sending
message sequence “07ELSZ”, for example. *Tx delay* (set on the *File |
Settings | Advanced* tab) should be no larger than necessary.
Experiment with setting *Split Operation* to both *Rig* and *Fake It*
on the *File | Settings | Radio* tab. Doppler tracking by *Own Echo*
might work better than *Constant Frequency on Moon*.

Measurements of noise from the Sun, Moon, and ground are made relative
to that from a suitable "cold sky" direction. For example, you may
want to make potential improvements to your system that will maximize
the difference between *Level* when pointed at the Sun, and when
pointed away by several beamwidths or more. Click *Monitor* to start a
continuous sequence of noise measurements.

=== Tips for EME

Until the advent of Q65, digital EME has mostly been done with JT65A
on the 50 MHz band, JT65B on 144 and 432 MHz, and JT65C on 1296 MHz.
On higher microwave bands typical choices have been JT65C, one of the
wider JT4 submodes, or QRA64, depending on the expected 
Doppler spread.  We now recommend a suitable submode of Q65 (which has
replaced QRA64) for EME on any VHF or higher band: for example,
Q65-60A on 50 and 144 MHz, Q65-60B on 432 MHz, Q65-60C on 1296 MHz
and 2.3 GHz, Q65-60D on 3.4 and 5.7 GHz, Q65-60D or E on 10 GHz, and
Q65-60E on 24 GHz and higher bands. 

JT4, JT65, and Q65 offer message averaging -- the summation of
successive transmissions conveying the same message -- to enable
decodes at signal-to-noise ratios several dB below the threshold for
a single transmission.  JT4 and JT65 also allow *Deep Search* decoding,
in which the decoder hypothesizes messages containing known or
previously decoded callsigns and tests them for reliability using a
correlation algorithm.  JT65 and Q65 offer _a priori_ (AP)
decoding, which takes advantage of naturally accumulating information
during a QSO. These options can be activated from the *Decode* menu.

With a CAT-controlled radio, _WSJT-X_ can be used to compensate for
changing Doppler shifts during a CW EME QSO. This capability is
especially useful on the higher microwave bands, where Doppler shifts
are large. Put your rig in CW mode and set the option *File | Settings
| Radio | Mode | None* to prevent _WSJT-X_ from trying to change the
operating mode. Use the *Tune* button to switch between receiving and
transmitting. No tones will be transmitted as the rig is in CW mode;
but importantly WSJT-X knows you are transmitting and adjusts the dial
frequency as needed for the currently selected Doppler tracking mode.
Click *Tune* again to revert to receive mode, reactivating the proper
Doppler corrections for receiving.

_WSJT-X_ supports the use of large additional offsets in dial
frequency for transmitting and receiving -- for example, to allow EME
QSOs between countries with amateur frequency allocations at 2304 and 2320
MHz. To use the feature, first set the Sked frequency to the frequency
you want to use for receiving in the normal way. Next, select the
amount you want your transmitted frequency to be shifted.  The figure
below shows an example of a station receiving on 1296 MHz and
transmitting on 1298 MHz. In this case, a Tx shift of +2 MHz has been
selected.

image::shift2.png[align="center",alt="Split Settings"]

TIP: To avoid the dial frequency indicator turning red, you may want
to add both transmit and receive frequencies to the Frequencies Table.