Hi All,
along with the new FT8 mode we reduced the built in delay between PTT
and audio starting. It was such that audio started at the beginning of
the next second. This meant that PTT was asserted soon after the
beginning of a transmit period and audio started at the beginning of the
next second (second 1). This was recently reduced to the start of the
next 1/2 second (0.5s into the Tx period) for the FT8 mode. The change
was made to allow a bit more decoding and thinking time at the end of an
Rx period.
The change above has revealed some deficiencies in the timing of the
start of Tx audio when CAT commands are executed before PTT is asserted.
Here is the commentary on a change I have just committed (r7756) that
tries to fix that:
Smarter Tx sequencing that allows for CAT processing latency
When using split operating and/or rig mode setting there is a delay
before PTT is asserted while the CAT commands are processed. There
will even be a small delay if CAT is only used for PTT. This change
waits for these commands to be completed before starting the user Tx
delay specified in the settings.
There is a notable exception to this in that DX Lab Suite Commander
does not give us a way of knowing when CAT commands have actually been
completed. This combined with the way that Commander spaces CAT
commands, rather than being paced by the rig's CAT responses, means
that delays of more than 1 second are likely. As most rigs suffer some
sort of ALC overshoot when PTT is asserted with audio already present,
it is strongly recommended not to use the DX Lab Suite Commander as a
rig control proxy if your rig may suffer ALC overshoot and you use an
external PA. Please note that using a typical RF power meter to detect
ALC overshoots is unwise as they are rarely fast enough. It is
probably wise to assume that all rigs suffer ALC overshoot since it is
very difficult to design an ALC loop that avoids it.
This change also increases the range of the "Settings->Advanced->Tx
Delay" spin box to 0s up to 2s.
73
Bill
G4WJS.
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