Wednesday, March 13, 2019

73 - More important than ever!


The purpose, use, and necessity of sending "73" codes as the final salutation of each party in a conversation (QSO) between Amateur Radio Operators (AROs aka HAMs) has been the subject of divergent opinion - especially among those bent on shortening the already incredibly short 1.75 minute length of an FT8 digital mode QSO from the initial "CQ" to the final "73".  This has led to some oft-times contentious, if not heated, debates about the necessity of the issuance of the last, closing "73" by both parties.

A quick review of such social intercourse suggests opinions in 3 main groups -  those who:
  • seek a full and proper logging of a QSO to its respectful and full conclusion resulting in a mutually agreed to confirmation of transmission (QSL).  Call them "Pro Formas".
  • are interested in contests and seeking the fastest way to log rare or heavily sought locations (QTHs) such as "DXpeditons" to rare locations like remote islands. Call them "Contesters".
  • treat QSL-ing as a casual activity and do not care about a full and proper exchange that maximizes the certitude of both parties of the overall QSL status. Call them "Casuals".

Craftspeople: The 1st group is those wishing complete and respectful forms of QSL with each party doing their very best to assure each other that the QSO was properly confirmed and logged to their complete and mutual satisfaction.

Track Team: The 2nd group is more concerned with maximizing the number of QSLs made in the shortest time since the ARO being sought (the "Fox") is often chased by 10's of AROs ("Hounds") and are willing to forgo certitude for increased QSL rates. There is something to be said about both modi operandii - with neither superseding or obviating the other.

Bar Hops: The 3rd group doesn't care much about certitude, mutual assistance, or pro forma protocol. For them, QSL-ing is a casual pastime wherewith they prefer to do the minimum to enjoy sporadic contact.   Much like dropping by a pub to share a few rounds with strangers who seem to share some interests but aren't inclined devote much time with - unless some chemistry intervenes.

Before deconstructing the minimum structure of a QSL, let's take a moment to review the de facto minimum of transmission message types from the initial CQ to the final 73.  For this example, let us use the wildly popular FT8 digital transmission mode which, by design, distills the essence of a complete QSL transmission to the least number of message types - 7 to be exact - each of which is transmitted within synchronized alternating 15 second time intervals, buckets, or packets. That's 7 x 15 = 105 seconds = 1m 45s, assuming the digital transmission software (WSJT's, e.g.) auto message sequencing is enabled, all messages are received, and all are responded to immediately.


Table 1a: Standard steps and formats for an FT8 transmission and QSL
#Message FormatExampleRemark
1CQ Oper1 GridCQ KT1TK FN42KT1TK from Grid FN42 calling anyone.
2Oper1 Oper2 GridKT1TK WD4HIP EL96Hi, this is WH4HIP from Grid EL96.
3Oper2 Oper1 SigDBWD4HIP KT1TK -04Hello. Your signal's -4db, what's yours?
4Oper1 Oper2 SigDBKT1TK WD4HIP +02Yours is +2db. Please confirm receipt.
5Oper2 Oper1 RRRWD4HIP KT1TK RRRGot your report. Please confirm to close?
6Oper1 Oper2 73KT1TK WD4HIP 73Ready to close. Confirm you are, too!
7Oper2 Oper1 73WD4HIP KT1TK 73We're good to log. Thanks for QSL. 73.

The essential and respectful aspect of this intercourse is that both parties ensure the other has what they need with their matching 73's.  This not only conforms to social etiquette and common decency, it also fulfills the mandate of AROs to help other AROs and to spread goodwill across the world - a fundamental tenet of their licensure. Remember your studies and exam questions, right?


Table 1b: Steps reduced by 1 if initial message targets a specific call.
#Message FormatExampleRemark
1CQ Oper1 GridWD4HIP KT1TK FN42KT1TK from Grid FN42 calling WH4HIP.
2Oper1 Oper2 SigDBKT1TK WD4HIP -04Hi KT1TK, your signal's -4db. What's mine?
3Oper2 Oper1 SigDBWD4HIP KT1TK +02Your signal's +2db. Please confirm.
4Oper1 Oper2 RRRKT1TK WD4HIP RRRGot report. Please confirm QSL?
5Oper2 Oper1 73WD4HIP KT1TK 73Ready to QSL. Confirm you got this!
6Oper1 Oper2 73KT1TK WD4HIP 73We're good to log. Thanks for QSL. 73.


Concatenated message code RR73 eliminates one step.

Can the number of messaging steps be reduced even further whilst maintaining proper etiquette and respect for the other party?  Yes, but carefully. Later versions of the FT8-like digital protocols allow for the sending of a combined "RRR" and "73" in the form of a "RR73".  As shown below, this eliminates one cycle (a) without sacrificing etiquette or integrity of the QSL certification, (b) reduces the cycles to 6 and (c) also changes who says the final goodbye 73.

Table 2a: Reducing 7-step CQ call to 6 by using concatenated response, "RR73"

#Message FormatExampleRemark
1CQ Oper1 GridCQ KT1TK FN42KT1TK from Grid FN42 calling anyone.
2Oper1 Oper2 GridKT1TK WD4HIP EL96Hi, this is WH4HIP from Grid EL96.
3Oper2 Oper1 SigDBWD4HIP KT1TK -04Hello. Your signal's -4db, what's yours?
4Oper1 Oper2 SigDBKT1TK WD4HIP +02Yours is +2db. Please confirm receipt.
5Oper2 Oper1 RRRWD4HIP KT1TK RR73Got report. Ready to close. Please confirm.
6Oper1 Oper2 73KT1TK WD4HIP 73We're good to log. Thanks for QSL. 73.

Using RR73 reduces even further the already reduced cycles of a directed message exchange (one that is initiated with a directed call (not a CQ to anyone), dropping the cycles to 5.


Table 2b: Reducing 6-step directed call to 5 by using concatenated response, "RR73"
#Message FormatExampleRemark
1CQ Oper1 GridWD4HIP KT1TK FN42KT1TK from Grid FN42 calling WH4HIP.
2Oper1 Oper2 SigDBKT1TK WD4HIP -04Hi KT1TK, your signal's -4db. What's mine?
3Oper2 Oper1 SigDBWD4HIP KT1TK +02Your signal's +2db. Please confirm.
4Oper1 Oper2 RRRKT1TK WD4HIP RR73Got report. Ready to log. Please confirm!
5Oper2 Oper1 73WD4HIP KT1TK 73We're good to log. Thanks for QSL. 73.


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