[Moon-net] QSO or not?

[Kelley, John D. (HQ-CF000)]

De K4WY
I hope this helps.  R = a transmission has been received correctly and
in full.  An RST report describes the readability, strength, and tone of
a signal but does not covey the same information as "R"   ACK anyone?
Also please consult CCSDS ISO Data and Communications Standards for
computer communications protocols and space applications.

Source:
ARRL Communications Procedures
Voice		Code	Situation
Go ahead	K	Used after calling CQ, or at the end of a
transmission, to indicate any 			station is invited to
transmit.
Over		AR	Used after a call to a specific station, before
the contact has been 				established.
		KN	Used at the end of any transmission when only
the specific station 				contacted is invited to
answer.
Stand by	AS	A temporary interruption of the contact.
Roger		R	Indicates a transmission has been received
correctly and in full.
Clear		SK	End of contact. SK is sent before the final
identification.

The RST System

Readability

1--Unreadable 
2--Barely readable, occasional words distinguishable. 
3--Readable with considerable difficulty. 
4--Readable with practically no difficulty. 
5--Perfectly readable.
 
Signal Strength
1--Faint signals, barely perceptible. 
2--Very weak signals. 
3--Weak signals. 
4--Fair signals. 
5--Fairly good signals. 
6--Good signals. 
7--Moderately strong signals. 
8--Strong signals. 
9--Extremely strong signals.
 
Tone
1--Sixty cycle a.c or less, very rough and broad. 
2--Very rough a.c., very harsh and broad. 
3--Rough a.c. tone, rectified but not filtered. 
4--Rough note, some trace of filtering. 
5--Filtered rectified a.c. but strongly ripple-modulated. 
6--Filtered tone, definite trace of ripple modulation. 
7--Near pure tone, trace of ripple modulation. 
8--Near perfect tone, slight trace of modulation. 
9--Perfect tone, no trace of ripple or modulation of any kind. 
If the signal has the characteristic steadiness of crystal control, add
the letter X to the RST report. If there is a chirp, the letter C may be
added to so indicate. Similarly for a click, add K. The above reporting
system is used on both cw and voice, leaving out the "tone" report on
voice. Turn card over for examples.  RST defines the readability, signal
strength and tone of a signal but does not presume the same importance
of "R" meaning message received.

ITU Phonetic Alphabet
Word list adopted by the International Telecommunications Union 
A--Alfa 
B--Bravo 
C--Charlie 
D--Delta 
E--Echo 
F--Foxtrot 
G--Golf 
H--Hotel 
I--India 
J--Juliett 
K--Kilo 
L--Lima 
M--Mike 
N--November 
O--Oscar 
P--Papa 
Q--Quebec 
R--Romeo 
S--Sierra 
T--Tango 
U--Uniform 
V--Victor 
W--Whiskey 
X--X-ray 
Y--Yankee 
Z--Zulu 
 

-----Original Message-----
From: moon-net-bounces at list-serv.davidv.net
[mailto:moon-net-bounces at list-serv.davidv.net] On Behalf Of Stewart
Nelson
Sent: Wednesday, May 02, 2007 8:50 AM
To: moon-net at list-serv.davidv.net
Subject: Re: [Moon-net] QSO or not?

Hi Jimmy and all,

> Could you please explain to me how is possible to have a QSO as 
> complete in the log of an expedition, when the station calling them
says it is not complete?
> However, expedition says it has data files for all QSOs. So does the 
> station trying to work them. So where is the error?
 
It's not necessarily an error.

With any unreliable communication medium, even if the system never
delivers an incorrect or false message, there is a significant chance
that the parties will disagree as to whether a QSO is complete.  It is
impossible to design a protocol to avoid this.  It doesn't matter if you
are using CW, WSJT, or smoke signals.  It's just common sense:

At the start of the QSO, both A and B know it is incomplete.  Each
station determines that his QSO is complete, when he *receives* the last
of whatever acknowledgements are required.  It is obvious that one
station will reach this decision before the other.  Let's say it's
station A.  At this point, if conditions change such that B never
receives another valid message, then B must assume that the QSO is
incomplete.

For example, in a classic EME QSO, station A might record a complete QSO
when he receives RO and sends RRR; station B when he receives RRR and
sends 73.  In this case, if RRR is never received, A shows complete; B
incomplete.
It does not help to make the requirements more stringent or the protocol
more complicated.  For example, if station A decides to consider the QSO
complete only if he receives 73, then if RRR is received but 73 is not,
A shows incomplete; B complete.

If desired, you can communicate out-of-band to resolve any ambiguity.
This is what happens in contests when logs are compared.  A mismatch
does not necessarily indicate any operator dishonesty or negligence;
it's just the way the laws of nature work.

If you could solve this problem, you would be a very rich man, because
there are many real world applications where it is important.  For
example, when you withdraw cash from an ATM, many things can (and do) go
wrong with the machine or the network.  The bank wants to be certain
that they don't debit your account, unless you have actually received
the cash.  But they also want to be certain that if you did receive the
cash they do debit your account.
Unfortunately, there is no protocol that can do the job.  If, just after
the server commands the ATM to release the money, the line goes dead,
there is no way to be sure whether you got the cash or not.  How are
these ambiguous cases resolved?  By out-of-band communication.  The ATM
prints a record of its activities on a local tape.  When the technician
comes to refill the machine, the tape is removed, physically transported
to the bank, and reviewed to resolve any discrepancies.  Gee, isn't this
just like using the Internet or a QSL card to know if the other party
had a complete QSO?
Don't you think that if there were an in-band solution that the pros
would have adopted it?  An alternate communication channel is sometimes
a necessity.

Of course, matters get much worse when you have a system that delivers a
false or incorrect message.  Unfortunately, any system practical for EME
(adequate sensitivity and speed) may occasionally provide an invalid
message.  It's up to the operator to use any available metadata (e.g.
"?" flags, signal level, frequency change) to minimize the probability
of misinterpreting a message.

--Stewart KK7KA

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