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WSJT-X supports short-codes and in
modes like JT65 they are not merely historical artefacts, they are
a very efficient mechanism of passing a 3-bit binary piece of
information (RO, RRR, or 73), i.e. a confirmation of receipt or
signoff. Short-codes are detected by the decoder with enhanced
sensitivity, not just used visually on the waterfall, although as
they have no FEC other than repetition, they may be interpreted
visually by the operator even if the decoder fails to recognize
them. To that end markers are drawn on the waterfall to aid visual
detection, each short-code consists of an alternating tone between
the lowest sync tone and another frequency denoting which
short-code it is.
A QSO might go like this (repetition
and message averaging elided), meanings of messages exchanged
CQ G4WJS IO91 # G4WJS makes a general call
G4WJS K1JT FN20 # K1JT replies
K1JT G4WJS OOO # G4WJS acknowledges the K1JT call
RO # K1JT acknowledges (short-code)
RRR # G4WJS acknowledges (short code
73 # K1JT signs off (short-code)
Note that even though 'OOO' is printed
nothing is sent in the message meaning 'OOO', instead any message
of the form "<DX-call> <DE-call> <grid-square>"
(where <grid-square> is optional) is simply printed, when
short-codes are enabled, as an 'OOO' message. I.e. the 'OOO' is
not a short-code message, it is just a decoration at the Rx end on
a normal 72-bit payload JT65 message.
MSK144, commonly used for
meteor-scatter QSOs below 2m, uses a different type of short-codes
which are full fledged messages which are shortened by various
reduced sensitivity encoding techniques in order to increase the
message repeat rate. The intent is to utilize shorter duration
meteor trails to complete a QSO in progress quickly, with some
sacrifice of sensitivity and decoding robustness. These are not
human readable other than that there is a clear audible difference
between a normal MSK144 message and a MSK144 short-code message,
determining which particular short-code message has been received
requires systematic decoding by software.
On 14/10/2020 23:23, Joe Subich, W4TV
Any objections to this proposed enhancement to DXKeeper?
The "shorthand" reports are becoming less frequently used as
more users adopt WSJTX to replace the older WSJT due to the
automation built into WSJT. As Bill points out the shorthand
reports are an artifact of CW (where they were easier to
recognize by ear) and the original WSJT (where they were easy
to "see" in the waterfall). The shorthand reports have little
if any advantage given the improved decoding in the most recent
versions of WSJTX. Logging the actual receive levels is just
as common as the shorthand reports.
I don't see the need for unique defaults - at least for those
using WSJTX or WSJTX/JTAlert given their integration with
DXLab Suite. The bigger issue with WSJTX/JTAlert is entering
propagation mode on a QSO by QSO basis - particularly if one
is running the K1JT modes on a second rig not controlled by
Commander at the same time as "traditional modes" on a rig
connected to Commander.
... Joe, W4TV
On 2020-10-14 6:00 PM, Dave AA6YQ wrote:
# even more AA6YQ
* more AA6YQ comments below
+ Are "OOO and RO" appropriate for JT65 in all
cases, or only when
the propagation mode is set to EME?
Only for EME
* Thanks, Joe. With the propagation mode set to EME, are
"OOO and RO" appropriate as default signal reports for all K1JT
modes, or just JT65?
* 000 is the default "RST sent" and "R0" is the default "RST
Rcvd" - correct?
those types of reports are optional even in JT65 mode. In
general they are used when fixed dual alternating tones are used
instead of encoded messages for the acknowledgement and sign off
stages of QSOs. These so-called short codes have increased
sensitivity allowing QSOs to be completed with marginal
propagation and station equipment. They hark back to CW EME
operating where repeated single charcters or pairs of characters
are sent for a complete period, i.e. OOOOOOO..., RORORORO...,
RRRRRRR..., 737373737373... . They are used, by prior agreement,
after callsigns are exchanged using regular messages.
# Thanks Bill! Based on your comments above and the "EME QSOs"
section of the document Iain N6ML recommended:
# it would seem appropriate for DXKeeper to use OOO and RO as
the default signal reports when the Propagation Mode implies
very weak signals: EME, Meteor Scatter (MS), and Tropospheric
# Any objections to this proposed enhancement to DXKeeper?