locked Re: PTT (TX) to audio time delta #general

Ron / W4MMP

Hi Bill,

Thanks for the response.  MSCC implements a very limited  set of TS-2000 CAT commands based on what I have captured from WSJT-X.   PTT Method is via RTS only (using the same com line as the CAT).

At any rate, the MSCC T/R switch over time is set to 5ms (the relay has a 3ms switch time).  This is well under the numbers you have provided.   Things are working well.  I just wanted to make sure I was not bumping into the WSJT-X switch delta. 

Ron / W4MMP
On 6/6/2021 04:26, Bill Somerville wrote:

On 05/06/2021 16:20, Ron / W4MMP via groups.io wrote:
Hi Bill,
Just a quick question on what is the delta time between WSJT-X setting
PTT (TX) ON and when WSJT-X starts the audio stream?

Background:  To prevent hot keying the RX/TX relay in rig we are
developing,  the application (MSCC) delays keying the PA for fixed
amount of time to give the RX/TX relay time to switch to TX.  I just
want to make sure that switch over delay is less than the WSJT-X delta.

Ron / W4MMP
Hi Ron,

the relationship is not straightforward. Nominally audio starts 500 mS
after the start of the period for FT8 mode. PTT is commanded at the
start of the period but if the CAT control is able to report PTT status
then WSJT-X delays audio start until PTT is confirmed. There is also a
parameter in "Settings->Advanced->Tx delay" that defaults to 200 mS.


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