// Status=review
=== Standard Exchange
By longstanding tradition, a minimally valid QSO requires the exchange
of callsigns, a signal report or some other information, and
acknowledgments.  _WSJT-X_ is designed to facilitate making such
minimal QSOs using short, structured messages. The process works best
if you use these formats and follow standard operating practices. The
recommended basic QSO goes something like this:

 CQ K1ABC FN42                          #K1ABC calls CQ
                   K1ABC G0XYZ IO91     #G0XYZ answers
 G0XYZ K1ABC –19                        #K1ABC sends report
                   K1ABC G0XYZ R-22     #G0XYZ sends R+report
 G0XYZ K1ABC RRR                        #K1ABC sends RRR
                   K1ABC G0XYZ 73       #G0XYZ sends 73

*Standard messages* consist of two callsigns (or CQ, QRZ, or DE and
one callsign) followed by the transmitting station’s grid locator, a
signal report, R plus a signal report, or the final acknowledgements
RRR or 73.  These messages are compressed and encoded in a highly
efficient and reliable way.  In uncompressed form (as displayed
on-screen) they may contain as many as 22 characters.  Some operators
prefer to send RR73 rather than RRR.  This is workable because RR73 is
encoded as a valid grid locator, one unlikely ever to be occupied by
an amateur station.

*Signal reports* are specified as signal-to-noise ratio (S/N or SNR) in dB,
using a standard reference noise bandwidth of 2500 Hz.  Thus, in the
example message above, K1ABC is telling G0XYZ that his
signal is 19 dB below the noise power in bandwidth 2500 Hz.  In his next
transmission, G0XYZ acknowledges receipt of that report and
responds with a –22 dB signal report.  JT65 reports are constrained to
lie in the range –30 to –1 dB, and values are significantly compressed
above about -10 dB.  JT9 supports the extended range –50 to +49 dB and
assigns more reliable numbers to relatively strong signals.

NOTE: Signals become visible on the waterfall around S/N = –26 dB and
audible (to someone with very good hearing) around –15 dB. 

NOTE: Several options are available for circumstances where fast QSOs
are desirable.  Double-click the *Tx1* control under _Now_ or _Next_
to toggle use of the Tx2 message rather than Tx1 to start a QSO.
Similarly, double-click the *Tx4* control to toggle between sending
`RRR` and `RR73` in that message.  The `RR73` message should be used
only if you are reasonably confident that no repetitions will be
required.

=== Free-Text Messages

Users sometimes add friendly chit-chat at the end of a QSO.
Free-format messages such as "`TNX ROBERT 73`" or "`5W VERT 73 GL`"
are supported, up to a maximum of 13 characters, including spaces.  In
general you should avoid the character / in free-text messages, as the
program may then try to interpret your construction as part of a
compound callsign.  It should be obvious that the _WSJT-X_
protocols are not designed or well suited for extensive conversations
or rag-chewing.

=== Auto-Sequencing

The T/R cycles of many _WSJT-X_ modes allow only a few seconds to
inspect decoded messages and decide how to reply.  Often this is
hardly enough time, so the program offers a basic auto-sequencing
feature.

Check *Auto Seq* on the main window to enable this feature:

image::auto-seq.png[align="center",alt="AutoSeq"]

When calling CQ you may choose to select *CQ: First* to reply
automatically to the first decoded responder, or *CQ: Max Dist* to
reply to the most distant responder, or the strongest or weakest
responder.

NOTE: When *Auto-Seq* is enabled, the program de-activates *Enable Tx*
at the end of each QSO. _WSJT-X_ will not make consecutive, 
fully automated QSOs.  Auto-sequencing is an operator aid, not an
operator replacement.

[[WAIT_FEATURES]]
=== Wait Features

Three wait-to-transmit features are available: *Wait and Reply*, *Wait
and Call* and *Wait and Pounce*. Enable these features through a checkbox near
the bottom of the *File | Settings | General* menu. When they are
enabled, the *DX Call* field and *Enable Tx* button turn yellow to
warn you that an automatic transmission may occur when a specified
condition is met. Be alert, and take any necessary precautions!

image::wait1.png[align="center",alt="wait1"]

.Wait and Reply

If a callsign is present in the *DX Call* field, *Wait and Reply* will
attempt to continue your QSO when that station sends you a
message. For example, you may have called station K1ABC, received no reply
and stopped transmitting when K1ABC replied to someone else. If K1ABC then
calls you, your QSO will resume automatically. This feature also
ensures that you will send a second RR73 if your first one is not
answered. *Wait and Reply* is effective for all modes where
auto-sequencing is available and a callsign is present in the *DX
Call* field.

NOTE: Especially if *Enable Wait features* is checked, it's good
practice to clear the *DX Call* field after a QSO.  Use the *F4* key
or right-click on the *DX Call* button.

.Wait and Call

*Wait and Call* is useful if the station you wish to work disappears
for a time, perhaps in a deep fade. To enable the feature, click on the
*DX Call* label, which will turn red if a callsign is present in the
*DX Call* field. When the station is decoded again sending a message
containing CQ, RR73, RRR or 73, you will call him automatically up to
three times. Any manual intervention, such as pressing the *Halt Tx*
or *Stop* buttons, will disable *Wait and Call* and give you the
normal manual control over the QSO.

.Wait and Pounce

*Wait and Pounce* can be used to answer a CQ from another station with
specific selection criteria.  To activate *Wait and Pounce*, ensure
that the *DX Call* box is empty and select one of the applicable CQ
categories from the drop-down list on main window.  Then right-click
on the *Enable Tx* button, which will turn orange. In your next Tx
sequence a reply will be sent automatically to a CQing station that
satisfies your chosen selection rule.

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

TIP: When using *Max Dist*, *Max dB*, or *Min dB* the program
automatically prevents working dupes. Information for this
worked-before decision is obtained from from file `wsjtx.log` in the
log directory. Stations in this file will be ignored by *Wait and
Pounce* and when you are calling CQ. To reset everything, click on
*File | Erase wsjtx.log*. Do not accidentally erase the file
`wsjtx_log.adi`, which contains your primary logbook!

*Wait and Pounce* works in concert with the *Filters* feature. For
example, you can wait for CQ messages containing a certain prefix,
grid, callsign, or keyword.

[[CONTEST_MSGS]]
=== Contest Messages

The FT4, FT8, and MSK144 protocols support special messages optimized
for *NA VHF* and *EU VHF* contests.  FT4 and FT8 also support messages
for *ARRL Field Day*, *FT Roundup*, *WW Digi*, and *ARRL International
Digital Contest*.  The decoders recognize and decode these messages at
any time.  Configure the program to automatically generate the
required message types for contest exchanges and carry out suitable
auto-sequencing by selecting a supported operating activity on the
*File | Settings | Advanced* tab.  Model QSOs then proceed as follows,
for each event type:

*NA VHF Contest* and *ARRL International Digital Contest*

 CQ TEST K1ABC FN42
                       K1ABC W9XYZ EN37
 W9XYZ K1ABC R FN42
                       K1ABC W9XYZ RRR
 W9XYZ K1ABC 73

Either callsign (or both) may have /R appended to signify a Rover in a
VHF contest.  You can use RR73 in place of RRR, and the final 73 is
optional.


*EU VHF Contest*

 CQ TEST G4ABC IO91
                                 G4ABC PA9XYZ JO22
 <PA9XYZ> <G4ABC> 570123 IO91NP
                                 <G4ABC> <PA9XYZ> R 580071 JO22DB
 PA9XYZ G4ABC RR73

Either callsign (or both) may have /P appended.

*ARRL Field Day*

 CQ FD K1ABC FN42
                       K1ABC W9XYZ 6A WI
 W9XYZ K1ABC R 2B EMA
                       K1ABC W9XYZ RR73

*FT Roundup*

 CQ RU K1ABC FN42
                       K1ABC W9XYZ 579 WI
 W9XYZ K1ABC R 589 MA
                       K1ABC W9XYZ RR73

*WW Digi Contest*

 CQ WW K1ABC FN42
                       K1ABC S52XYZ JN76
 S52XYZ K1ABC R FN42
                       K1ABC S52XYZ RR73


Contest QSOs are generally treated as invalid when they appear in one
station's log and not the supposed QSO partner's.  To avoid Not-in-Log
(NIL) penalties for yourself and others, we recommend the following
guidelines for contest logging with FT4, FT8, and MSK144:

 - Activate and learn to use the *Alternate F1-F6 bindings* selectable
   on the *File | Settings | General* tab.
 
 - Always log a QSO when you have received RRR, RR73, or 73 from a
   station you are working.

 - Log a QSO when you send RR73 or 73 if you are reasonably confident
  it will be copied. But be sure to watch for any indication that it
  was not copied, and then take appropriate action. For example, if
  you receive the Tx3 message (R plus contest exchange) again, and if
  you have activated the *Alternate F1-F6 bindings*, hit *F4* to
  re-send your RR73.

[[COMP-CALL]] 
=== Nonstandard Callsigns

*Modes with 77-bit message payloads: FST4, FT4, FT8, MSK144, and Q65*

Compound callsigns like PJ4/K1ABC or K1ABC/3 and special event
callsigns like YW18FIFA are supported for normal QSOs but not for 
contest-style messages.  Model QSOs look something like this:

 CQ PJ4/K1ABC
                       <PJ4/K1ABC> W9XYZ
 W9XYZ <PJ4/K1ABC> +03
                       <PJ4/K1ABC> W9XYZ R-08
 <W9XYZ> PJ4/K1ABC RRR
                       PJ4/K1ABC <W9XYZ> 73

Compound or nonstandard callsigns are automatically recognized and
handled using special message types.  One such callsign and one
standard callsign may appear in most messages, provided that one of
them is enclosed in <  > angle brackets.  If the message includes a
grid locator or numerical signal report, the brackets must enclose the
compound or nonstandard callsign; otherwise the brackets may be around
either call.

Angle brackets imply that the enclosed callsign is not transmitted in
full, but rather as a hash code using a smaller number of bits.
Receiving stations will display the full nonstandard callsign if it
has been received in full in the recent past.  Otherwise it will be
displayed as < . . . >.  These restrictions are honored automatically
by the algorithm that generates default messages for minimal QSOs.
Except for the special cases involving /P or /R used in VHF
contesting, _WSJT-X_ offers no support for two nonstandard callsigns
to work each other.

TIP: Using a nonstandard callsign has definite costs.  It restricts
the types of information that can be included in a message.  It
prevents including your locator in standard messages, which
necessarily impairs the usefulness of tools like PSK Reporter.

*Modes with 72-bit message payloads: JT4, JT9, and JT65*

In the 72-bit modes, compound callsigns are handled in one of two
possible ways:

.Type 1 compound callsigns

A list of about 350 of the most common prefixes and suffixes can be
displayed from the *Help* menu.  A single compound callsign involving
one item from this list can be used in place of the standard third
word of a message (normally a locator, signal report, RRR, or 73).
The following examples are all acceptable messages containing *Type 1*
compound callsigns:

 CQ ZA/K1ABC
 CQ K1ABC/4
 ZA/K1ABC G0XYZ
 G0XYZ K1ABC/4

The following messages are _not_ valid, because a third word is not
permitted in any message containing a *Type 1* compound callsign:

 ZA/K1ABC G0XYZ -22        #These messages are invalid; each would 
 G0XYZ K1ABC/4 73          # be sent without its third "word"

A QSO between two stations using *Type 1* compound-callsign messages
might look like this:

 CQ ZA/K1ABC
                     ZA/K1ABC G0XYZ
 G0XYZ K1ABC –19
                     K1ABC G0XYZ R–22
 G0XYZ K1ABC RRR
                     K1ABC G0XYZ 73

Notice that the full compound callsign is sent and received in the
first two transmissions.  After that, the operators omit the add-on
prefix or suffix and use the base call and standard structured
messages.

.Type 2 Compound callsigns

Prefixes and suffixes _not_ found in the displayable short list are
handled by using *Type 2* compound callsigns.  In this case the
compound callsign must be the second word in a two- or three-word
message, and the first word must be CQ, DE, or QRZ.  Prefixes can be 1
to 4 characters, suffixes 1 to 3 characters.  A third word conveying a
locator, report, RRR, or 73 is permitted.  The following are valid 
messages containing *Type 2* compound callsigns:

 CQ W4/G0XYZ FM07
 QRZ K1ABC/VE6 DO33
 DE W4/G0XYZ FM18
 DE W4/G0XYZ -22
 DE W4/G0XYZ R-22
 DE W4/G0XYZ RRR
 DE W4/G0XYZ 73

In each case, the compound callsign is treated as *Type 2* because the
add-on prefix or suffix is _not_ one of those in the fixed list.  Note
that a second callsign is never permissible in these messages.

NOTE: During a transmission your outgoing message is displayed in the
first label on the *Status Bar* and shown exactly as another station
would receive it.  You can check to see that you are actually
transmitting the message you wish to send.

QSOs involving *Type 2* compound callsigns might look like either
of the following sequences:

 CQ K1ABC/VE1 FN75
                     K1ABC G0XYZ IO91
 G0XYZ K1ABC –19
                     K1ABC G0XYZ R–22
 G0XYZ K1ABC RRR
                     K1ABC/VE1 73


 CQ K1ABC FN42
                     DE G0XYZ/W4 FM18
 G0XYZ K1ABC –19
                     K1ABC G0XYZ R–22
 G0XYZ K1ABC RRR
                     DE G0XYZ/W4 73

Operators with a compound callsign use its full form when calling CQ
and possibly also in a 73 transmission, as may be required by
licensing authorities.  Other transmissions during a QSO may use the
standard structured messages without callsign prefix or suffix. 

TIP: If you are using a compound callsign, you may want to
experiment with the option *Message generation for type 2 compound
callsign holders* on the *File | Settings | General* tab, so that messages
will be generated that best suit your needs.

TIP: If you are using a compound callsign, it is recommended to
use a *Tx1* message and not a *Tx2* message when calling another station.
This will ensure that the station you are calling will be able to decode your
callsign in full.

=== Pre-QSO Checklist

Before attempting your first QSO with one of the _WSJT-X_ modes, be sure
to go through the <<TUTORIAL,Basic Operating Tutorial>> above as well
as the following checklist:

- Your callsign and grid locator set to correct values

- PTT and CAT control (if used) properly configured and tested

- Computer clock properly synchronized to UTC within ±1 s

- Audio input and output devices configured for sample rate 48000 Hz,
16 bits

- Radio set to *USB* (upper sideband) mode

- Radio filters centered and set to widest available passband (up to 5 kHz).

TIP: Remember that in many circumstances the _WSJT-X_ modes do not
require high power. Under most HF propagation conditions, QRP is the
norm.
