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

[width="90%",cols="3,^3,^3,^4,10",options="header"]
|=======================================
|UTC|To|From|Grid/Rpt|Comment
|0001|CQ|K1ABC|FN42|~ K1ABC calls CQ
|0002|K1ABC|G0XYZ|IO91|~ G0XYZ answers
|0003|G0XYZ|K1ABC|–19|~ K1ABC sends report
|0004|K1ABC|G0XYZ|R–22|~ G0XYZ sends acknowledgment and report
|0005|G0XYZ|K1ABC|RRR|~ K1ABC sends acknowledgment
|0006|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, acknowledgement R plus a signal report, or the final
acknowledgements “RRR” or “73”.  Messages are compressed and encoded
in a highly efficient and reliable way.  

*Signal reports* are specified as signal-to-noise ratio (S/N) in dB,
using a standard reference noise bandwidth 2500 Hz.  JT65 reports must
lie in the range –30 to –1 dB, while JT9 supports the extended range
–50 to +49 dB.  Thus, in example message #0003, K1ABC is telling G0XYZ
that his signal is 19 dB below the noise power in bandwidth 2500 Hz.
In message #0004, G0XYZ acknowledges receipt of that report and
responds with a –22 dB signal report.

TIP: For operators with very good hearing, signals become audible
around S/N = –15 dB and visible on the waterfall to –26 dB. The JT65
decoder begins to fail around –24 dB, JT9 around –26 dB.

*Free Text Messages*: Users often add some friendly chit-chat as a
final transmission, in place of the formatted ``73'' message.
Free-format messages such as ``TNX JOE 73 GL'' or `5W VERT 73 GL'' are
supported, up to a maximum of 13 characters (including spaces).  It
should be obvious that JT9 and JT65 are not suitable for extensive
conversations or rag-chewing.

=== Compound Callsigns
//This section needs work!  Must describe and give examples for both 
//JT65v1 and JT65v2 formats.
Compound call-signs such as PJ4/K1ABC or G0XYZ/P are handled in a slightly 
different way.  The following formats are all valid:

.Valid Messages with Compound Callsigns

[width="40%",cols="2,2,2",options="header"]
|=====================
|Action|Callsign|Grid
|CQ|pfx/callsign|grid
|QRZ|pfx/callsign|grid
|DE|pfx/callsign|grid
|CQ|callsign/sfx|grid
|QRZ|callsign/sfx|grid
|DE|callsign/sfx|grid
|=====================

- ``pfx'' is a 1-4 character prefix
- ``callsign'' is a standard callsign
- ``sfx'' is a 1-3 character suffix
- ``grid'' is a 4-character Maidenhead locator

- A signal report of the form “±nn” or “R±nn”, or the acknowledgment
or sign-off messages “RRR” or “73”.  {wsjtx} generates messages in
these forms automatically, as required.

- A QSO between two stations using compound call-signs might look like this:

 CQ KP4/K1ABC FK68
                     DE G0XYZ/P IO91
 G0XYZ K1ABC –19
                     K1ABC G0XYZ R–22
 G0XYZ K1ABC RRR
                     DE G0XYZ/P 73

////
.Compound Exch Example
[width="40%",cols="2,2,2",options="header"]
|=====================
|Action|Callsign|Grid
|CQ|KP4/K1ABC|FK68
|DE|G0XYZ/P|IO91
|G0XYZ|K1ABC|–19
|K1ABC|G0XYZ|R–22
|G0XYZ|K1ABC|RRR
|DE|G0XYZ/P|73
|=====================
////
=== Pre-QSO Checklist

Before attempting your first QSO with JT9 or JT65, be sure to go
through the <<X15,Basic Tutorial>> above and 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 with UTC to within ±1 s
- Radio set to USB (upper sideband) mode
- Radio's Split mode selected or not, consistent with your choice on
*Station* tab of *Configuration* window.

- Remember that JT9 and J65 generally do not require high power. Under
most propagation conditions, [red]*QRP is the rule!*