// 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. *Signal reports* are specified as signal-to-noise ratio (S/N) 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 the message at 0004, 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. Thresholds for decodability are around -20 dB for FT8, -23 dB for JT4, –25 dB for JT65, –27 dB for JT9. === Free-Text Messages Users often add some 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 JT4, JT9, and JT65 protocols are not designed or well suited for extensive conversations or rag-chewing. === Auto-Sequencing The slow modes JT4, JT9, JT65, and QRA64 allow nearly 10 seconds at the end of each one-minute receiving sequence -- enough time for you to inspect decoded messages and decide how to reply. The 15-second T/R cycles of FT8 allow only about two seconds for this task, which is often not enough. For this reason a basic auto-sequencing feature is offered. Check *Auto Seq* on the main window to enable this feature: image::auto-seq.png[align="center",alt="AutoSeq"] When calling CQ you may also choose to check the box *Call 1st*. _WSJT-X_ will then respond automatically to the first decoded responder to your CQ. NOTE: When *Auto-Seq* is enabled the program de-activates *Enable Tx* at the end of each QSO. We do not want _WSJT-X_ to make fully automated QSOs. [[COMP-CALL]] === Compound Callsigns Compound callsigns such as xx/K1ABC or K1ABC/x are handled in one of two possible ways: .Messages containing 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 standard structured messages. .Type 2 Compound-Callsign Messages 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 will 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 *Settings | General* tab, so that messages will be generated that best suit your needs. === Pre-QSO Checklist Before attempting your first QSO with one of the WSJT modes, be sure to go through the <> 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 - 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 FT8, JT4, JT9, JT65, and WSPR do not require high power. Under most HF propagation conditions, QRP is usually the norm.