In my opinion, there are some reasons why FT8/4 users think that the
RR73's and 73's are needed, even though they shouldn't be:
1. WSJT-X decided to implement synchronous transmissions with a 4-frame
transmit sequence. The 4th frame is really needed only for the purpose
of maintaining synchronization, so they threw in the last 73 as filler.
The WSJT-X documentation essentially states this, and by now users have
gotten used to it enough that they think it is necessary for confirmation.
2. WSJT-X is an all-or-nothing decode. It's great for eliminating
busted transmissions but removes any evidence that somebody tried (and
partially failed) to reply to you. In CW or SSB or even RTTY, if one
side gives you a busted acknowledgement with the right timing and
cadence, you can usually infer that he got your transmission. That isn't
possible with WSJT-X, which essentially has traded busts for NILs.
3. FT8 in particular has a long contact cycle ... a full minute and
each frame takes fifteen seconds. Propagation can change pretty
radically in a minute ... even within fifteen seconds ... and the chance
of good copy turning into bad copy is much greater than for the one or
two seconds between you giving me a report and me saying TU CQ on CQ,
SSB, or RTTY. The uncertainty is greater, especially with an all or
nothing decode.
4. Per some of the recent posts in this thread, some users and even
core developers behind WSJT-X keep telling people that the extra RR73's
and 73's are necessary, even though they shouldn't be.
FT4 reduces some of these issues simply because it is quicker, and
contesters could address some of the rest simply by agreeing to do so,
but some of the issues are fundamental to how WSJT-X implements a
superior weak signal protocol.
73,
Dave AB7E
On 2/28/2020 10:12 AM, John Kludt wrote:
Claude,
As was said early in this thread, open to many interpretations. When
contesting on CW or phone once the exchange has been sent both ways,
the fact that the initiating station calls CQ or goes onto
another station is taken as evidence that the QSO is complete. There
is no exchange of "QSL's" or "73's". In fact for the hard core saying
things like "Thank you" are considered extra words that just slow you
down. Why is an increased level of assurance needed for this mode?
Other than it is easy to do, at least in theory.
John
John
On Fri, Feb 28, 2020 at 11:24 AM Claude Frantz
<claude.fra...@bayern-mail.de <mailto:claude.fra...@bayern-mail.de>>
wrote:
On 2/27/20 10:13 PM, Reino Talarmo wrote:
Hi Reino & all,
> I agree your comment on RRR or RR73 being confirmation of
reception "R" ack.
> There is a minor difference though RR73 is "I am fully happy and
don't
> expect any further response from you", while RRR is usually
taken to mean "I
> received you confirmation, but I want to be sure that you
received my
> confirmation as well (before logging this QSO)" and then 73 from
you is that
> confirmation of confirmation. Some even want a 73 to that 73 as
confirmation
> of the confirmation of the confirmation!
Many thanks for pointing to this little but very important difference.
In few words: The QSO is complete when both stations have received
"73"
(or "RR73") from the other station, without error.
Best wishes,
Claude (DJ0OT)
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